The Power Sources Manufacturers Association (PSMA) announces a series of webinars as a lead-up to the next edition of the PSMA Power Technology Roadmap (PTR). The webinar series, organized by the PSMA Power Technology Roadmap Committee, will feature invited experts from different fields to offer a range of technological perspectives. In addition to setting the groundwork and providing input for the next PTR, the webinars will give participants access to expert opinions on technology trends and include a question and answer session at the end of each session.
As in previous seasons, the webinar series will include a number of highly regarded industry and academic experts covering a variety of topics covering components, systems, packaging and applications. The series began on July 28 with a presentation by Victor Veliadis of PowerAmerica "SiC Power Technology Status and Barriers to Overcome." A second webinar was held on August 25 presented by Professor Mike Ranjram of Arizona State University "Coupled Electronic and Magnetic Systems for High Performance Power Electronics." Webinars are scheduled for September and beyond covering a wide range of topics including horticultural lighting, the benefits of GaN in BLDC Motor Drives and many other topics.
Webinars are tentatively scheduled to be held every other Thursday from 10:00-11:00 a.m. US Central Time. For updates to the schedule and news of webinars that will be added, please visit: www.psma.com/technical-forums/roadmap/news-events and follow us on LinkedIn and Twitter. To join the PSMA mailing list to receive invitations to all upcoming webinars, sign up at www.psma.com/webforms/psma-email PSMA gratefully acknowledges the generous support provided to the 2021-22 PTR series by the following underwriters: Gold - RECOM Power GmbH; Silver - Applied Materials, Infineon, Wolfspeed, Würth Elektronik. If your company is interested in underwriting the webinars in 2023, please contact the PSMA Office at firstname.lastname@example.org.
The Power Technology Roadmap provides a consolidated outlook of trends in power conversion technology for the next two to five years. The trends provided in the report are intended to give a broad outlook of the power conversion technologies, components and applications. The complete Roadmap document has been published every two or three years, incorporating the content of the Roadmap Webinars Series conducted over the months prior to publication. The other content for the report is sourced from a wide range of recognized industry experts and comprises write-ups about trends in components, applications, emerging technologies and university research. It also includes a comprehensive projection of key metrics evolution in four selected power conversion technologies (ac-dc front-end power supplies, ac-dc external power supplies, isolated dc-dc converters and non-isolated dc-dc converters).
Conor Quinn of Advanced Energy and Dhaval Dalal of ACP Technologies, Power Technology Roadmap Committee Co-chairs, stated; "The PTR webinars provide a window into technology trends and the presentations are unique in terms of their diversity of perspectives, commercial-free tone and the opportunity they offer for the audience to interact with industry experts. We are always looking to enrich and expand our panel of webinar presenters and we welcome suggestions and proposals from prospective speakers." Joe Horzepa, PSMA Executive Director, added that the Committee "welcomes and invites subject matter experts who are willing to actively participate and contribute to the development of the next PSMA Power Technology Roadmap to contact the PSMA Association Office at email@example.com."
Other news of interest
Four members of the Board of Directors are elected at the PSMA Annual Meeting held every year, usually during the APEC conference. Each Director serves a three-year term and is eligible to be reelected for one additional term. In this issue we would like to introduce you to Dhaval Dalal and Renee Yawger.
Principal, ACP Technologies
Dhaval Dalal is a power electronics consultant, specializing in power architecture definition, design guidance, competitive benchmarking and evaluation/refinement of strategic direction all geared towards renewable energy proliferation and high efficiency power solutions.
From 2014-2020, Dhaval was at ON Semiconductor, where as a Business Unit Director, he was responsible for defining and providing components for high power solutions to customers. His prior experience includes stints at TI/Unitrode, Digital Equipment Corporation and Philips Laboratories.
Dhaval's educational background includes a B.Tech. (EE) from IIT-Bombay, an MSEE from Virginia Tech and a Master's in Management of Technology from NTU. He is currently pursuing a PhD in Electrical Engineering at ASU in the field of renewable energy integration. He has published and presented more than 25 technical articles, papers and invited talks. He serves as the co-chair of the PSMA (Power Sources Manufacturers' Association) Power Technology Roadmap Committee and on the Board of Directors of PSMA and is also a participant in the iNEMI roadmap activity. Dhaval has served as a co-chair of Industry Sessions Program Committee for APEC since 2021. Dhaval holds five U.S. patents.
Provided by Dhaval Dalal, Principal, ACP Technologies
Director of Marketing at Efficient Power Conversion (EPC),
Director Corporate Marketing at EPC Space
Renee Yawger has over 25 years of sales and marketing experience within the semiconductor industry. Prior to joining EPC, she was at Vishay Siliconix for nearly 15 years in various positions in sales support, customer service, and regional marketing. At EPC, Renee is responsible for the product marketing and marketing communications functions globally.
Renee serves as Vice President of the Power Sources Manufactures Association (PSMA) as well as a member of the Semiconductor Committee, involved with organizing session(s) on semiconductor devices and applications for the Applied Power Electronics Conference (APEC). She also contributed to the 2022 PSMA Power Technology Roadmap, authoring the chapter on GaN Discrete Devices Under 200 V, and as a co-author on the chapter on GaN ICs. Renee is a contributing author to the textbook GaN Power Devices and Applications.
Provided by Renee Yawger, Director of Marketing, Efficient Power Conversion (EPC)
Power supplies are everywhere, an essential part of all electronic equipment. Whether powered by battery or from the grid, there are as many power solutions as there are applications. From body sensors powered by harvested energy to high power systems for medical imageries such as MRI, medical power supplies, all have a common requirement to be safe, reliable and energy efficient. While the large majority of medical equipment requires conventional power supplies compatible with their operating environment, in effect running a marathon by delivering steady power day after day during their lifetime, there are certain categories of applications that require a power supply able to deliver peak power, either occasionally or repetitively. For these applications medical equipment manufacturers must consider a number of parameters to ensure that the power supply they select will be able to not only run a marathon but in certain specific applications be able to perform a sprint race without compromising safety, performance or reliability.
What to consider when a marathon requires sprint race performance?
While it is assumed for medical equipment manufacturers that a power supply must comply with safety standards (EN/IEC 60601-1), the output performance is very much dependent on the final equipment's load behavior. While in monitoring and supervising systems the power consumption remains relatively stable and easy to predict, in medical equipment such as medicalized beds, infusion pumps, assisted patient ventilation that includes DC motors, and electromechanical-switches behaving as inductive or capacitive loads, the power supply may at times have to deliver extra power for a period of few milliseconds to seconds (Figure 01). Though the duration time for peak power may be considered short compared to a normal operating time, it still needs to be seriously considered to avoid costly surprises.
Figure 01 – Infusion pumps and typical peak load behavior (Source: PRBX/ Superstar-Shutterstock)
In addition to the output voltage and power, the type of load will determine what factors are important for the system designer to consider. There are many possibilities and in some equipment the main power supply could power a variety of systems and sub-systems with different load profiles which is obviously more complex to address. To simplify, we will list four basic types of loads: inductive, capacitive, constant current, and nonlinear resistive. Each of them has a specific behavior requiring attention when selecting a power supply for each such applications.
Loads types in short:
Inductive load: Loads such as motors and electromagnetic switches (e.g., relays, magnet switches) with an inductive characteristic are referred to as inductive loads. At the moment of applying a voltage to a DC-motor, a current multiple times the rated value will flow through the load; while at the moment of cutting the voltage off, due to the inductive component of the load, a voltage of counter electromotive force E= -L× (di / dt) will be generated. Generally, when applying a voltage to an inductive load the power supply can sustain the energy required by the peak demand only up the limit of its overcurrent protection (OCP) function (Figure 02). Exceeding the limit, even if only for a very short time, can cause the power supply to stop. This is the reason why the peak load must be well defined in order to select an appropriate power supply with an overcurrent protection that allows the surge power for a definite time and sequence. Also, when turning the output voltage off, due to the counter electromotive force generated (in most cases, it is absorbed by the electrolytic capacitors in the power supply), the overvoltage protection circuit of the power supply may be triggered, and the power supply cease output. In this case measures such as including a reverse voltage protection diode should be exercised.
Capacitive load: A load with a capacitance component is called a capacitive load. For example, the capacitors inserted for the purpose of reducing the ripple voltage of the power supply, and capacitors used for coping with peak loads, etc. For this kind of load, at the moment of applying a voltage a very large charging current ipeak = (V/R) with R being the (parasitic) series resistance, will flow due to there being no charge in the capacitor. Although the power supply can detect and control the output voltage, if a large value capacitor (over several tens of thousands of microfarads) is inserted into the output side, such control may not be able to realize what is happening, and the output voltage may become unstable. It is important for system designers to consider the total amount of capacitance installed in their equipment and to verify the power supply's ability to deliver the required peak energy needed to efficiently charge the load which in some applications could be several Farads.
Figure 02 – Typical overcurrent protection curves (Source: PRBX/ COSEL)
Constant current load: A load where the current stays constant although the load voltage varies is called a constant current load, an example being LED lighting in surgical theaters. It is important to consider the type of overcurrent protection built into the power supply. If for example the overcurrent protection characteristic of the power supply is a current fold back type, the output voltage may not be able to rise (Figure 02). This is because the output voltage stabilizes on the drooping line of the overcurrent protection characteristic of the power supply from applying a voltage to reaching the rated voltage. Generally, by changing the overcurrent protection characteristic to a maximum current limiting type the problem can be solved.
Non Linear Resistive: Some equipment uses heating elements or lamps with filaments where the resistance changes when current flows through it. Though this warm up phase with a monotonic resistance change might only last for a short time, for the power supply it may look like a constant current exceeding the threshold value for its built-in overcurrent protection.
Overcurrent protection is a very important part of a power supply. It guarantees the power unit in the case of an excess power situation that may occur accidentally or as result of an equipment failure, will protect the equipment and will eventually flag the fault by way of a signal to the operator, e.g. a LED or a signal transmitted by the communication BUS.
Overcurrent protection overview
As previously explained, when the output current/power exceeds a defined limit, several types of damage could occur within the power supply or in the equipment being powered. Besides preventing the current from exceeding a rated value, the protection circuit also plays the role of limiting short circuit current. Depending on the type of application and specific system requirements, when OCP is activated a number of effects may result, the output could be switched off permanently with a manual reset, switched off temporarily with an automatic reset, or behave as a fixed, but safe level constant current (Figure 02).
Figure 03 – Peak current at startup when charging capacitors (Source: PRBX)
When a power supply or an electrical device is turned on, high initial current flows into the load, ramping up until it reaches a peak value. The main reason for this initial peak is to charge the large decoupling or smoothing capacitors within the power supply and final equipment. During this sequence, as the capacitors charge or devices come out of a cold state, the current increases very quickly from zero, rising all the way to the peak current and then decreasing gradually to the steady state current (Figure 03). During this period the power supply must deliver enough energy to charge the capacitors, and supply the required power to the load without activating the over-current protection (OCP) thus shutting down the output. Also, some loads might initially behave as a short-circuit and require the power supply not to go into protection mode. To accommodate this start-up sequence, power supplies are designed to allow a certain level of overcurrent, and it is common to set the OCP threshold at around 110% of the maximum rated value.
110% is good enough for the vast majority of applications though in the case of demanding medical equipment requiring peak power levels in the range of 200-300% for seconds, 110% will not suffice, requiring a power supply designed not only to deliver a high peak power, but to guarantee the highest reliability during the overall lifetime of the final equipment.
Running a marathon at sprint performance levels!
A simple way to guarantee the power supply will deliver enough energy when extra surge power is required is to choose a power unit rated for the maximum power required during the peak demand. For example, if the maximum steady power required by an apparatus is 500W and the peak is 1000W, then taking into consideration the operating conditions e.g., input voltage, environmental temperature, derating, etc., the system designer could consider a 1200W power supply as the most suitable solution.
This seems to be obvious, but is overkill when the peak is only happening occasionally. For example when a DC motor is activated for positioning a patient's bed then switched off and the power supply is again only powering the control system. Similarly this would be overkill for systems requiring repetitive peak loads for a limited time compared to steady state power.
Choosing a power supply for peak load applications requires one to evaluate the operating conditions during the lifetime of the equipment, and to take into consideration all aspects including size, weight and price. Buying a 1200W power supply, when peak load represents only a limited portion of the operation, might not be the best option.
Power supply manufacturers have developed power solutions able to deliver significant extra power in the range of twice nominal, or even more than the maximum rated, for a significant duration. This requires the power unit to be designed to host enough capacitors (Figure 04) but also to have a power-train able to sustain repetitive peak demands without over-heating or adversely affecting reliability.
Figure 04 – Design equation to guarantee output capacitors to sustain required peak energy (Source: PRBX)
As an example, consider the output voltage behavior of the COSEL 600W AEA600F series (Figure 05) when applying a peak load to the output. The tested product is a 600W rated power unit, delivering 24V at a nominal current of 25A. As presented in Figure 06, the power-train and output capacitors have been selected to sustain a peak power twice nominal for a duration of 1000 milliseconds. Two conditions are represented in Figure 06: From no load to 52.5A peak, and from 12.25A half-load to 52.5A peak. In both conditions, the voltage remains within the specified limits, and OCP is not shutting down the output.
Figure 05 – COSEL 600W power supply for medical applications with peak load capacity up to 300% (Source: PRBX/COSEL/WHYFRAME-Shutterstock)
Figure 06 – COSEL AEA600F peak load test in two conditions (0 to 200% and 50% to 200% load) (Source: PRBX/COSEL)
Running a marathon with sprint-race performance levels in medical power supplies is a reality, and while the great variety of applications require different types of power supplies, technology is making it easier for system designers to choose the right products for their applications. This is without mentioning the fantastic opportunities brought about by new technologies such as Wide Band Gap semiconductors, Supercapacitors, and digital control coming to the next generation of power supplies, and making power designers' lives so exciting.
Provided by Patrick Le Fèvre
At the APEC 2022 Plenary Session, John H. Scott, Principal Technologist, Power and Energy Storage, NASA Space Technology Mission Directorate presented a very interesting topic: 'On the Moon to Stay', covering the various aspects of power electronics that would be required to make that statement feasible. Space exploration has not only been a dream and a source of imagination, but also an amazing research area seeking to break 'unbreakable' limits, and in the processing providing benefits to many applications we are now using daily on planet Earth.
Figure 01 - O’Neill Cylinder interior - Painting by Rick Guidice (Source: PRBX/NASA)
Taking humans first to the moon, later to Mars and who knows where to next, is far from being an easy job; making life possible and sustainable in such hostile environments is much more than just 'a challenge'. One example is how to feed the space explorers when they are so remote from planet Earth? When considering Mars, it would take 210 days and a significant cost and risk for a re-supply rocket to arrive, which is clearly not an optimum solution. Space farming has been part of that dream and we all remember the O'Neill Cylinder, designed by Princeton physicist Gerard K. O'Neill who published in 1974 an article in Physic Today: 'The Colonization of Space'. O'Neill's article and research fueled a number of sci-fi movies showing the huge rotating cylinder, hosting farms and lit by an artificial sun (Figure 01). We are not there yet, but on that basis the first humans to inhabit Mars may be considered farmers more so than astronauts! So how will power electronics contribute to make the dream a reality?
From Earth indoor farming to Space: Feeding 10 billion people on Earth
Let's start by looking at Earth. If we consider the latest estimation, Earth's population is expected to reach 10 billion by 2050. Simultaneously we are facing climate changes that could impact the complete food ecosystem and require significant modifications to the ways in which we produce and consume food.
Considering all the parameters and requirement to produce food with the highest respect for the environment, in 1999, Dr. Dickson Despommier with his students developed the idea of modern indoor farming, revitalizing the terms coined in 1915 by the American geologist Gilbert Ellis Bailey: "Vertical farming." We have all heard about it and even read articles about industrial buildings that were converted into vertical farms, but from the early days using fluorescent or halogen lighting to Solid State Lighting (SSL), there have been an amazing number of technological innovations that contribute to the effort to optimize the energy delivered to the plants for optimal growth. With these advances, the benefits of indoor farming multiplies. If we consider space utilization, 100 times more food could be produced per square meter compared to traditional agriculture, reducing water utilization by 90% and hazardous chemicals to none. Indoor farming is very attractive but to be really efficient such agriculture requires a very efficient lighting system (Figure 02).
Figure 02 - Solid State Lighting to grow vegetables in indoor farming (source PRBX / asharkyu-Shutterstock)
Not all vegetables can grow with limited soil and nutrition by impregnation but for the ones compatible with this farming method, the results are impressive and can be further improved by using modern lighting technologies that are computer-controlled. This is very interesting area which for power designers to explore, combining advanced power electronics and modern agriculture, while keeping software in mind.
Since its introduction, indoor farming engineers conducted research to determine the spectrum and energy required by different plants to grow efficiently. From wide spectrum fluorescent or halogen lamps to narrower spectrum, the conventional lighting industry innovated a lot but these technologies are not flexible nor efficient enough to respond to the demand.
Figure 03 - The light spectrum to grow plants and vegetables typically starts at 450 nm (blue light) and goes through 730 nm (far red) (source PRBX)
In Japan from 2005-2008, agronomical researchers experimented with different lighting methods to adjust spectrum and energy to specific plants. Researchers concluded that the optimal light spectrum to grow plants and vegetables typically starts at 450 nm (blue light) and goes through 730 nm (far red) (Figure 03). The Photosynthetic Photon Flux Density (PPFD) required ranges from 50 micromoles (µmol) for mushrooms up to 2,000 micromoles for plants like tomatoes and some flowers that thrive in full summer light (Figure 04).
Figure 04 - Light energy required ranges from 50 micromoles (µmol) for mushrooms up to 2.000 micromoles for light intensive plants (source PRBX)
Agricultural experts advise that for optimal results different plants require different light spectra as well as differing light balances and intensities at different stages of growth, from seedling through harvest. This often results in the need for the artificial light to have a number of different spectra channels that are individually adjustable for intensity. Some crop growing practices combine different sources of lighting, including the use of UV flashes to prevent the development of parasites, requiring a power supply able to switch from constant voltage to constant current within a range from almost zero to the maximum (Figure 05). This specification for a power supply is very much what will be required for Space Farming, in addition to a power electronics architecture able to combat the effects of space radiation.
Bringing Earth farming to Space
As NASA plans long-duration missions to the Moon and Mars, a key factor is figuring out how to feed crews during their weeks, months, and even years in space. Food for crews aboard the International Space Station (ISS) is primarily prepackaged on Earth, requiring regular resupply deliveries. Now, while it is feasible for the ISS to be resupplied by cargo spacecraft, clearly it would be much more complicated and expensive to use this method on Mars, which is at an average distance of 220 million km (140 million miles) and more than 200 days traveling.
Figure 05 – COSEL power supply with multi-modes for voltage or current constant from max to near zero (Source PRBX/COSEL)
In 2015, NASA in association with the Fairchild Botanical Gardens in Miami began a project called 'Growing Beyond Earth' to define what plants would be suitable for autonomous space-farming. After a series of experiments which took into consideration the full development cycle, the variety of plants that were selected for further research included lettuces, mustard varieties, and radishes. These crops were first grown in a controlled lab on Earth, then in the ISS to study how plants are affected by the micro-gravity and other factors (Figure 06).
Figure 06 - NASA astronaut Peggy Whitson looks at the Advanced Astroculture Soybean plant growth experiment (Source: PRBX/NASA)(Source PRBX/NASA)
The 'Veggie' project included a large number of experimental factors such as "Pick-and-Eat Salad-Crop Productivity, Nutritional Value, and Acceptability to Supplement the ISS Food System (Veg-04A)" and included research on the optimum lighting conditions to grow plants. On the ISS, two light treatments with different red-to-blue ratios were tested for each set of crops to define light colors, levels, and horticultural best practices to achieve high yields of safe, nutritious leafy greens and tomatoes to supplement a space diet of pre-packaged food, and later for Moon or Mars farming. A number of reports have been released including 'Large-Scale crop production for Moon and Mars: Current gaps and future perspectives' published in February in 'Frontiers in Astronomy and Space Sciences' summarizing seven years of experimentation on Earth and in the ISS (Figure 07).
https://www.psma.com/HTML/newsletter/pics/prbxa_047_figure_07_space-far…" width="90%" />Figure 07 – Examples of Kennedy Space Center 8KSC) prior, current and future space crop production platforms selected and designed to lead to crop production units destined for the Moon or Mars (Source PRBX/NASA)
Considering the different varieties of plants that will be grown, and the distance and cost, the power supplies for space-farming will have to accommodate different power profiles combining constant current or constant voltage, peak power, and must also be energy efficient and small in size. That's in addition to specific constraints related to space, including immunity to radiation, operating temperature, shock and vibration.
The importance of optimizing the payload, the weight and size of everything is a big concern for space applications. For all applications, from low orbit satellites to out-of-space exploration, power supplies have been developed with very advanced technologies to make them smaller and energy efficient.
Wide Band gap (WBG) semiconductors in space applications have formed a part of many research projects, and it's worth mentioning the report presented by NASA, in 2018, at the (RADECS) conference in Gothenburg: 'Radiation and its Effects on Components and Systems'. This identified the strengths and weaknesses of WBG when exposed to radiation. The recent announcement about the newly funded national collaboration led by Penn State to better predict and mitigate radiation-induced damage of WBG semiconductors is interesting. The U.S. Department of Defense awarded the team a five-year, $7.5 million Defense Multidisciplinary University Research Initiative Award. This clearly shows the high level of importance of WBG in space applications and their contribution to the next step.
In parallel, the semiconductor industry is moving forward. One example is the new division and products for space applications launched by Efficient Power Conversion (EPC). For power designers, having access to COTS ruggedized GaN for space applications will reduce the development time and cost when developing power supplies for space applications (Figure 08).
Figure 08 – Efficient Power Conversion (EPC) ruggedized GaN FET for space applications and DC/DC converter (Source: PRBX/EPC)
Although one of the biggest challenges to in-spaceship farming is sourcing enough water and nutrients and then cycling them as efficiently as possible, there are many other obstacles we don't have to grapple with on Earth that will need to be considered too, such as cosmic radiation, lack of an atmosphere, and low levels of light. From the 2015 'Growing Beyond Earth' project to current advances in 2022, a lot of progress has been made, contributing to a better understanding of space farming, as well as in power electronics. We are in the early stages of a whole new era in which Wide Bandgap semiconductors in power electronics will play an important role.
Exciting time for power designers, isn't it?!
The Colonization of Space – Gerard K. O'Neill, Physics Today, 1974
Fairchild Botanical Garden
NASA / RADEC 2018
Jean-Marie Lauenstein – NASA GSFC, Greenbelt, MD, USA
Wide-Bandgap Semiconductors in Space: Appreciating the Benefits but Understanding the Risks
Frontiers in Astronomy and Space Science
Large-Scale Crop Production for the Moon and Mars: Current Gaps and Future Perspectives
Published 04 February 2022 / doi: 10.3389/fspas.2021.733944
Efficient Power Conversion (EPC)
Applied Power Electronics Conference (APEC)
Patrick Le Fèvre
Chief Marketing and Communications Officer, Powerbox
The Power Sources Manufacturers Association (PSMA) is pleased to announce that a new slate of officers has been elected to lead its Board of Directors for the 2022-2024 term. The new officers are Fred Weber (Future Technology Worldwide), Chair; Trifon Liakopoulos (EnaChip Inc.), President; Renee Yawger (Efficient Power Conversion (EPC)), Vice President; and Tim McDonald (Infineon Technologies), Secretary/Treasurer.
Fred Weber expressed appreciation for Mike Hayes' leadership as Chair from 2020-2022. "The past 2 years have been difficult due to the unprecedented challenges of the pandemic and resulting impact on APEC2020 and 2021 and the many workshops sponsored and co-sponsored by the PSMA Technical Committees. Mike not only navigated these challenges but also focused the PSMA Executive Committee with a number of innovative and lasting projects." Fred looks forward to continuing this work and noted "PSMA's success relies on the active participation of our members, especially through the many Technical Committees. The Board welcomes and encourages all companies in our industry to become part of this unique industry organization."
The twelve members of the Board are elected by the member company representatives to serve three-year terms, with four members rotating off each year. The full board of directors for 2022-2023 are:
- Fred Weber, Future Technology Worldwide - Chair
- Trifon Liakopoulos, EnaChip Inc. – President
- Renee Yawger, Efficient Power Conversion (EPC) – Vice President
- Tim McDonald, Infineon Technologies – Secretary/Treasurer
- Ada Cheng, AdaClock
- Dhaval Dalal, ACP Technologies LLC
- Thomas Foulkes, Pacergy LLC
- Reenu Garg, Microchip Technology
- Ajay Hari, onsemi
- George Slama, Wurth Electronics
- Llew Vaughan-Edmunds, Navitas Semiconductor
- Brian Zahnstecher, PowerRox, LLC
As is the case in many industries, power electronics has been impacted by the Covid-19 pandemic. This includes a boost in new technologies and opportunities for power designers to capitalize on the benefits of E-learning. While it is always difficult to derive trends from large industries, as we get closer to APEC 2022, as a power engineer it is interesting to take a minute to ponder and consider what will contribute to making power supplies more efficient, more reliable and exciting to design.
Overall trends and technology
A major trend that we are all aware of is the 'electrification' and transition from fossil fuels to renewable energy. There are a lot of technological innovations required in this segment to reach the carbon neutral level expected by the European Commission, US DOE and similar initiatives in Asia. If we focus on what most of the power supplies companies are developing, I foresee that four trends, all of which will benefit from the implementation of Wide Band Gap Semiconductors, will influence the power industry in 2022:
- Reducing energy consumption
- Power supplies becoming part of the Machine-to-Machine eco-system
- Enhanced energy storage solutions
- Acceleration of harvesting energy solutions,
In the quest for reduced energy consumption, from harvesting energy to the grid, the power electronics industry is seeking new long term solutions to improve efficiency. International and local regulations have already forced power supply manufacturers to innovate, and we are seeing more stringent regulations under discussion that would require the power industry to further explore new topologies, components and materials.
One example that illustrates and will benefit from this trend is E-commerce.
E-commerce was already growing before Covid-19, but as consequence of curfews, working at home, and the drastic reduction of physical interaction, it has grown exponentially, putting a high demand on shipping hubs, computerized storage and the overall supply chain. Before we even mention the associated datacenters required to manage the E-commerce process, there are the shipping hubs and warehouses that have become gigantic and consume lots of energy. Making these hubs more energy efficient has been on the agenda for all the major players, and the 2020-2021 peak on demand was a strong a signal for the need to reconsider the way to use and to manage energy.
Figure 01: Smart Power operation in Smart Factory with machine-to-machine communication
Power supplies as such are not consuming the majority of this energy, but, when one considers their strategic position in the operational chain, they become a key point in the overall process to optimize how energy is used in the complete chain. In 2022 we will see very advanced power supplies used in E-commerce handling and shipping hubs. Not only will they integrate higher levels of communication, they will also be able to store and restore energy from supercapacitors banks, reducing peak disturbances on the grid and consumption. Already experimented with in 2021, the power supplies have been integrated into a complete eco-system with Machine-to-Machine communication (Figure 01). They not only deliver power to a load e.g. conveyor motors, but they are able to sense and adjust the level of energy to store in local supercapacitors bank (Figure 02).
Figure 02 - PRBX S-CAP BOOST supercapacitors bank with digital control and communication
interface able to deliver peak energy to load and to store backward energy
Almost invisible, from the RFID inserted in the shipping box that will get power from RF signals, to sensors placed on motors or moving elements powered by vibration, micro-systems powered by harvested energy are developing very quickly. Additionally, the nanotechnology, such as nanotubes, make it possible to develop very small supercapacitors able to store enough energy to power sensors and transmitters.
To make this possible, the implementation of digital power and communication is a must, but the level of performance will also require power electronics engineers to design new power solutions with the so called 'Wide Band Gap' semiconductors. Depending on the application and voltage required they may select GaN or SiC types, but the benefits of WBG will contribute to making E-commerce more energy efficient and to reducing the carbon footprint.
Critical building blocks!
For decades the improvements in energy efficiency levels of power supplies have been made possible by technological evolutions. Moving from linear to switching technology was an early major one, followed by a number of more minor leap-frogs until digital power came to market.
Despite it having been on the market for several years, with the emerging WBG technology and the possibilities offered by those components, digital control becomes an absolute MUST and I strongly believe it will be a major building block for power designers when developing new products.
For components, the WBG transistors are without doubt the ones that will prevail in 2022. That said, conventional Power FETs are also making big progress and power designers will have to achieve new levels of business assessment and acumen when selecting the most appropriate technology for their applications.
Figure 03 - PRBX multi-cores auto-tuned power converters with
advanced digital control and GaN FET transistors
The third building block I foresee as important is the advanced planar transformer with interleaved multi-core technology. Not all power supplies require megahertz switching but considering the constant quest for smaller power supplies with higher efficiency, power designers will have to consider new types of transformers and new winding techniques. In that respect they will not only be helped by ferrite manufacturers developing new materials but also by Artificial Intelligence software that can shorten the time to design and test new transformer types (e.g., Frenetic, Simba).
One specific example of this is research currently being conducted at PRBX, combining digital control, GaN, and multicore transformers with advanced wiring and auto-tuned performance within the wide operational range that is seen in some industrial applications that require extremely wide input voltage ranges, as well as outputs subject to repetitive peak loads. Final products while not ready yet will not be possible without the combination of digital control, WBG and advanced magnetics (Figure 03).
I believe many of the new products that we will see in 2022 and onwards will be based on these three building blocks, which I'm sure will also include more communication to become part of a Machine-to-Machine ecosystem.
In WBG we trust!
One interesting aspect about Wide Band Gap semiconductors is that we are seeing a similar situation to when the first power MOSFETs were launched. Some immediately considered the benefits of the WBG, despite early products that were based on a depletion mode that required very specific drivers and were not very user friendly, it didn't take too long for power semiconductors manufacturers to provide 'easy-to-use' solutions.
It has now been more than five years since manufacturers first promoted the benefits of that technology but if the Go To Market is ready, the Go To Application for mass users still requires a certain amount of time.
Figure 04 - Experienced power designers have crossed that technological chasm many times,
with the latest one being the migration from analog control to digital
We are all familiar with the 'camel-back' curve reflecting new technology adoption and crossing the chasm. Experienced power designers have crossed that technological chasm many times, with the latest one being the migration from analog control to digital, which took more than 10 years to reach a significant level of adoption (Figure 04).
Figure 05 - Navitas' next-generation GaNFast power IC that will drive the 120W ultra-fast charger, contributing to reduce its size by 26%
Figure 06 - Efficient Power Conversion (EPC) approach is very interesting, minimizing interconnection losses, and making it possible to shrink a power converter to an unprecedented size
In the case of WBG, and especially Gallium Nitride (GaN), early adopters entered the fray much quicker than some had predicted a few years ago. It is no surprise that the PC and Mobile/Nomad industries were some of the early adopters. The number of USB-C chargers using GaN semiconductors announced in 2020-2021 is very impressive. Particularly worthy of mention is Navitas' next-generation GaNFast power IC that will drive the 120W ultra-fast charger supplied 'in-box' with vivo's iQOO-brand flagship iQOO 9 Pro mobile phone, demonstrating the rapid adoption of GaN by the 'nomad' industry. But it is not just the electrical performance, using GaN also reduces the physical size by 26%, reaching a stunning 1.3W/cc power density, which is quite incredible (Figure 05).
While it took 10 years for digital power to become a de facto technology, it took only five years for WBG to reach a similar level.
What is interesting in the development of the WBG semiconductors is that due to the specificity of this technology, with very low internal resistance and the ability to switch very fast, the packaging is very important and we see a lot of innovation from manufacturers to offer optimized solutions. Technologywise the Efficient Power Conversion (EPC) approach is very interesting, minimizing interconnection losses, and making it possible to shrink a power converter to an unprecedented size (Figure 06).
Of note is the amazing number of technical webinars held during the Covid-19 era, not to mention the virtual APEC 2021. Many companies have taken that as an opportunity for their power designers to attend online training, and as a result some power-semiconductor companies have reported shipping up to 10 times more evaluation kits than before the pandemic days.
If we simplify the market into two segments: High voltage (using SiC) and Low voltage (using GaN), we see two different patterns. High voltage applications such as electric vehicles and solar are already familiar with SiC transistors, and for that segment it is no big revolution for power engineers to undergo a learning phase for the relatively new low voltage technology.
In many different ways we have all been affected by the pandemic, although looking back it has contributed to a boost in learning new technology and speeding innovation. Considering all of that, 2022 will be a very important year for WBG and we can expect many new power supplies (AC/DC and DC/DC) to be announced during the year. 2022 will be a very exciting year for all of us designing power solutions.
Powerbox (PRBX): https://www.prbx.com/
Navitas Semiconductors: https://navitassemi.com/
Efficient Power Conversion (EPC): https://epc-co.com/epc
Applied Power Electronics Conferences (APEC) https://apec-conf.org/
Provided by Patrick Le Fèvre
Hello Members and Friends of PSMA.
What an exciting year! APEC was back as an "in-person" event. I was thrilled to be able to see everyone again. Although with virtual events we were able to share information with the industry, nothing replaces face-to-face interactions and networking.
I am honored to be elected as Chair of PSMA accompanied by an extremely strong Executive Team comprising Trifon Liakopoulos (President), Renee Yawger (Vice-President) & Tim McDonald (Secretary/Treasurer).
I would like to thank our previous Chair, Michael Hayes for his dedication and focus leading PSMA during the past 2 very difficult years. His outstanding leadership allowed PSMA to successfully navigate a very challenging period of time.
PSMA intends to continue and to strengthen many of the policies that have been put into place the past few years. Our focus on becoming more applications specific continues. We are targeting several key industries: Smart Mobility (Transportation), Internet of Things (IoT), and Energy Storage. We are also continuing our efforts to foster alliances with other organizations. Our history with IEEE PELS and IEEE IAS is well known, as the three of us co-sponsor APEC. We also work closely with IPC, iNEMI, EPSMA, and CPSS on several cross promotional projects. Our latest alliance is with the IEEE Transportation Electrification Community (ITEC). This workshop is an excellent example of an applications specific offering that includes an alliance with a strategic organization.
One of our key internal strategies will be to facilitate more cross communication between the PSMA Technical Committees. PSMA functions largely around the efforts of the volunteers that support our 14 Technical Committees that organize Special Projects, our APEC Industry Sessions, Educational Webinars, support the Power Technology Roadmap, and other activities. With the advances in technology there is often an overlap in the focus of the committees, that can be better fostered. As an example, the focus and interests of the Transportation Electronics Committee has direct overlaps with the focus of the Energy Storage, Energy Management, and Semiconductor Committees. By joining forces, anything these groups offer will be enhanced. In order to encourage and to enable better communications, we are developing a liaison system for data and idea sharing to improve the end results of the Committee activities.
Finally, please let us know what you would like to see in the PSMA UPDATE newsletter. Suggestions are always welcome!
– Fred Weber, PSMA Chair
Professor Cian Ó Mathúna with the 2021 EARTO Innovation
Award for Impact Expected
ne of PSMA's long-time contributors and supporters, Professor Cian Ó Mathúna, from Tyndall National Institute in Cork, Ireland has been recently named the recipient of two major international awards celebrating innovative technology created in Ireland, which could have a lasting environmental impact.
Minimizing energy consumption in electronics continues to be a major, technological challenge. Responding to this challenge, Cian, who is currently Head of MicroNano Systems at Tyndall, has, over the last 27 years, developed MagIC (Magnetics on Silicon), an innovative technology that can greatly extend the battery life of portable electronics and dramatically reduce the energy use of high-performance electronic systems and equipment.
The ground-breaking impact of the technology has been recently recognized with prestigious awards from the 400,000 member IEEE (Institute of Electrical and Electronics Engineers) and EARTO (European Association of Research and Technology Organisations).
The IEEE Power Electronics Society Technical Achievement Award for Integration and Miniaturisation of Switching Power Converters celebrates Cian's extraordinary, global influence and leadership over the last decade in bringing together the electronics industry and academia to collaborate toward the development of the Power Supply-on-Chip (PwrSoC).
Tyndall is the first Irish recipient of an EARTO Award, which recognizes key contributions from European research to high-impact, technological innovation. The 2021 EARTO Innovation Award for Impact Expected looks to the future and recognizes the impact Professor Ó Mathúna's research will have on the technology of the future. Including dramatically reducing system energy consumption, extending battery life and reducing the overall size, weight and cost of future electronic systems.
Tyndall's MagIC technology makes bulky magnetics components in electronic equipment to disappear onto the silicon chip, just like Gordon Moore and colleagues did with the transistor over 50 years ago. Using MagIC technology, electronics will be able to use power more efficiently by minimizing the energy wasted or lost as the battery powers the multiple-voltage rails required in multi-core microprocessor chips and/or other complex SoC chips. This improved efficiency can extend the charge time of batteries by more than 50%. The breakthrough technology will have a huge impact on markets for mobile phones, IT equipment, and any device needing a battery. It is also envisaged that the technology will deliver significant energy savings in servers in the data centre and high-performance computing space.
Professor Ó Mathúna said, "This ground-breaking and disruptive innovation is set to change the global approach to how power is managed in electronic devices and will contribute to addressing a critical environmental issue for society and our planet. We continue to partner extensively with global companies to develop and commercialize the technology which has already received more than €20M in funding from research, licensing and productization. We have joint publications with companies such as Global Foundries in Dresden and Singapore; Intel, USA; Philips in the Netherlands, TI in the USA; Wurth Electronics in Germany as well as a joint patent with Apple Computers."
Cian joined the November 2021 PSMA Board of Directors meeting and was very gracious and effusive in acknowledging the influence PSMA has had on the emergence of PwrSoC over the last 3 decades. Cian mentioned that he was first introduced to PSMA by Don Staffiere who managed to convince one of his Irish clients, Gary Duffy, then MD of Computer Products (later Artseyn Technologies) to fund Cian's attendance at the 1994 APEC. Cian came to APEC with a very limited background in power electronics but, through Don's introductions to PSMA, he began participating in the PSMA Technology Roadmap initiative, and was quickly able to leverage his expertise in microelectronics packaging which was just beginning to have a very positive impact on the miniaturization and integration of power electronics products.
Joe Horzepa, Gary Duffy, Arnold Alderman and Cian Ó Mathúna at APEC in the mid 2000s
With the support of Don Staffiere, Bob Huljak, the late Prof. William Sarjeant and the strategic guidance and wisdom of Joe Horzepa (and Judy!), Cian engaged with Arnold Alderman and Doug Hopkins to run the Packaging Technical Committee with Brian Narveson and Ernie Parker later contributing their expertise. Around 1997/98, PSMA awarded NMRC (National Microelectronics Research Centre – the precursor to Tyndall) funding to undertake a special project on the state-of-the-art in commercial 3D power electronics packaging and followed this, in 2006/2007, with funding, for Tyndall and Anagenesis, on the very first study on fully-integrated power – the visionary and seminal "PSiP2PwrSoC" project.
Looking back, Cian sees this project as the inspiration for him to establish PwrSoC, the International Workshop on Power Supply on Chip which was first held in Cork in 2008 with over 100 international participants. At PwrSoC2010, Tyndall agreed to hand over the workshop to PSMA and the IEEE Power Electronics Society from which point the Workshop has become recognized as the flagship technical forum worldwide for both industry and academia to get together to discuss both the technological and business challenges and opportunities for PwrSoC.
In his closing remarks, Cian commented "the vision and strategic perspective of PSMA, over the last 27 years, has had a dramatic impact on seeding research in power electronics, on providing a dedicated forum to gain insight into major power industry challenges and, in particular, in providing me, and the wider team at NMRC/Tyndall, with the international perspective to succeed. For all of this, I am forever in PSMA's debt."
ver since their introduction, keeping the temperature of a power supply down to a level that guarantees the highest levels of performance and safety has been a major concern for power designers. Considering the amazing increase in power densities that we have witnessed during the last 20 years, thermal management has become a preponderant part of the design process. Layout and mechanical design are now as important as efficiency topologies, and how to evacuate the calories out of modules has become an art!
The race to get greater power density!
At the same time, with the development of mobile telecommunications the increased demand for integrated power solutions contributed to the emergence of the so called 'bricks', and a race to package more power into smaller sizes began. The increases of power have been really impressive. One example is the increase in power density of the so called 'quarter-brick'. In March 2000, the power modules division of ERICSSON (EPM) launched a state of the art 100W quarter brick DC/DC converter, the PKM 4000 series. 20 years later FLEX Power Module (which acquired EPM in 2017) launched a 1300W quarter brick, the BMR480 (Figure 01).
Increasing the output power by a factor of more than 10 in less than 20 years is the result of a combination of more efficient topologies, digital control, new components, heavy-copper multilayer PCBs, integrated magnetics and outstanding layouts. But in addition, to guarantee full performance of such products, efficient cooling is a must!
Keeping Fourier's Law in mind
As we all remember from school, in 1822 the French Physician Joseph Fourier (Figure 02) demonstrated that the time rate of heat transfer through a material is proportional to the negative gradient in the temperature and to the area. Fourier's laws (Figure 03) of thermal conduction governs the principle of heat exchange from the lowest level e.g., the semiconductor junction to ambient. Thermal resistance is the reciprocal of thermal conductance. Just as an electrical resistance is associated with the conduction of electricity, a thermal resistance may be associated with the conduction of heat. Making the thermal resistance as low as possible is a challenge for all power designers and that's where electronics meets thermodynamics.
The packaging practices of AC/DC and DC/DC power modules are optimized to evacuate the heat through a conduction cooling mechanism from silicon to an exchanger surface e.g., aluminum baseplate. In most common applications a heatsink is attached to the baseplate and cooled by a flow of air, thus evacuating heat from the module (Figure 04). In telecom/datacom applications, a 400 LFM (2 m/s) airflow circulating inside the rack to cool the overall system is very common, but some very high power density systems may require up to the double that (800 LFM (4 m/s)), which is very noisy and reduces the life time of fans and cooling turbines.
Air forced cooling is the most common method to keep the temperature within safe limits though there are a number of applications where such cooling methods are not possible. However, there are a growing number of concerns about reliability and sustainability related toforced air cooling. Usually the air ventilated through datacenters and other high power equipment is exhausted outside the building and the calories are not converted into any usable resource. Thereforemost of the datacenters require air-conditioning systems which consume a lot of energy, which is a major concern.
When forced air cooling is not an option
Industrial machinery such as laser cutting equipment that generates burnt particles, smoke, and steam have their monitoring and control boxes sealed to avoid contamination and the risk of damage as a result of the cutting process. In order to power the control system, the power supply is enclosed in a sealed box, thus requiring the dissipated heat to be extracted by conduction from the chassis, or the need for it to be attached to a cold-wall. To make the cooling as efficient as possible the power supply is designed with a large base-plate to which all dissipating components are attached (Figure 05). In some equipment a liquid cooling is required to cool vital parts, e.g., a laser or plasma torch during operation. In such applications the power supply benefits from the fluid circulation and the baseplate attached to a cooling element (Figure 06).
Industrial surveillance and safety equipment may be installed in remote places where exposure to extreme weather conditions is common, and where maintenance can become complicated. In such installations reliability is extremely important, and system designers need to exclude all possible causes of failure. Despite significant improvements in quality, fans and blowers are subject to mechanical failure and are not suitable for such applications. Again, as in the previous example, cooling can only be achieved through conduction to the outside of the sealed box and a passive heat exchanger.
When silence is golden
One example is open-landscape offices where in some cases noise levels can be as high as 60 to 65 decibels. This may seem minor compared to say a busy highway that generates 85 decibels, but it can make cognitively demanding work difficult and tiring to undertake, with subsequent effects on health and safety. In fact, a number of companies now require noise levels in open-landscape offices to be below 55 decibels.
In such situations, all of the equipment installed in the room which may include computers and large displays, such as those used in a road or air traffic control office, the noise levels must be reduced to the lowest level possible, and noisy forced air cooling is banned. Under such conditions the power supply must be designed to operate without ventilation, using a conduction cooling solution.
Théorie Analytique de la Chaleur par M. FOURRIER – 1822
FLEX Power Modules : https://flexpowermodules.com/
ver the years I have worked with various safety, compliance, and certification agencies and NRTLs (Nationally Recognized Testing Laboratories) and similar types of labs. Let's call them businesses who make money from certifying products of various sorts. In the past, before legal, finance and operations ruled the world, some of these agencies were not-for-profit organizations which were funded by insurance companies to enhance safety and minimize losses from coverage of fires and damages caused by unsafe conditions in products. Today many or all the NRTLs are businesses who charge like lawyers in billable hours.
This approach to safety and compliance certification has changed how test labs conduct business to the point where your success in obtaining certifications for your new product will depend to a large extent on which laboratory you choose to work with. And in my experience, your success will also depend on who you get assigned to at that particular NRTL. Success in this case involves meeting your goals for budget and time to market on your project. This article recounts a series of compliance stories, let's call them case studies, in which companies encountered difficulties in attempting to obtain safety certifications.
As these stories illustrate, there are a variety of pitfalls in the safety approvals process, often relating to the unfortunate choice of an NRTL that places profit over serving the customer. But as we'll also see, choosing the right NRTL and the right lab representative can not only avoid the nuisance problems caused by the laboratory, but also educate the customer on better design choices that will ultimately make compliance easier.
This article focuses on the problems that occur when companies seek safety compliance certifications. But before we delve into examples of these problems, let's consider some of the reasons why the choice of test lab is more of an issue with safety than with other compliance certifications.
How Safety Compliance Differs from Other Areas
First, let's define in today's landscape what compliance regulatory certifications are needed to make a product that can be sold in the marketplace. These include global environmental and materials certifications, radiated and conducted EMI-RFI, CE certification, energy efficiency standards, and electrical safety/flammability of materials. In some cases, all of these must be met. So, let's look at these areas one by one.
Environmental and materials content has turned into a mandatory disclosure area with penalties to the OEM for not conforming. While very onerous and time consuming, this process is pretty black and white. What components comprise your product inside the shipping box? And probably these days you must also disclose the contents of your shipping box, including cords and cables and perhaps even the composition of the box as well. Nevertheless, it's scientifically cut and dried.
With radiated and conducted emissions, you either meet the standard or you don't via methodology and measurements. It's pretty much a pass or fail situation and you want to pass with margin to account for production deviations.
CE is all about whether your product conforms to European health, safety, and environmental protection standards, which mostly encompasses the same items as RoHS and Reach. The CE certification is a super big deal in Europe but not a factor in the U.S. It's mostly obtained by hiring a consultant, paying them, and filling out documents in which you attest that your product adheres to the standards—tick a box and you get CE certification.
Energy efficiency standards, while they vary country by country and range from mandatory to voluntary, are also applied in scientific ways. You measure the energy consumed in various modes of operation and the product either conforms or not. If it doesn't, you re-spin the software or the hardware design until it meets the standards, and then you are certified to the standards. It's measured and validated, and again, data wins. It's a pass-fail situation. In some cases, you are allowed to self-disclose (self-certify the product).
However, what I have observed in the safety area has been very different from these other types of certifications. In my experience, it depends not only on the company you choose to certify your product, but also on who you get to work on your product certification at that agency. Without naming names of organizations, I have seen situations where one NRTL certifies a product or subsystem—and since we are in the power electronics industry lets be specific to merchant power supplies—but another NRTL rejects that certification.
The compliance process has become so challenging that some see this situation as a business opportunity. I was amazed to recently see an advertisement by a group of former NRTL test employees that will, for a fee, coach and guide you on how to get your product prepared for getting through the process at a specific, or perhaps all NRTLs. That's somewhat the reverse of a situation in the healthcare industry where insurance companies are paying retired dentists and doctors to help them reject or delay claims!
In theory, power supply makers usually will only need to get certification from one NRTL and all the other NRTLs are supposed to accept those test results. However, some labs have learned that doing so doesn't maximize billable hours. This statement is not meant to impugn all NRTLs. There are a lot of top-certificating organizations who are moral and ethical. But there are some for whom the guiding principle seems to be just "is it legal, and what can we get away with?" We'll see examples of both in the following stories.
Case 1: When NRTLs Don't Accept Each Other's Work
A large scientific instrument company designed a new instrument using a power supply which was previously certified by NRTL "A". This power supply meets not only the industrial standards that the instrument must conform to, it also meets medical electronic specifications IEC 60601 3rd edition and 4th edition EMC—both of which are more stringent specifications than that required of the industrial instrument. The power supply also meets IEC 62368 and legacy IEC 60950 IT power supply standards.
In this scenario, the instrument maker submitted their new instrument to NRTL "B" to certify its compliance with the applicable safety standards. Test lab B ran its tests and found that the product passed all tests. However, NRTL B questioned everything about the power supply and took exception to its previous certifications. They said they cannot accept the certifications from NRTL A, and the customer must completely re-certify and validate the conformance of the power supply to a standard to which it has already been tested and conformed. This would of course cost the instrument maker a great deal of time and money, while generating goodly income for NRTL B.
For the instrument manufacturer, the options included paying the NRTL to redo the testing, which was unnecessary, switching the project to another NRTL or redesigning the product with a power supply that the NRTL would find acceptable. It's likely that had the instrument company used another NRTL, the power supply would have been accepted and the product would have passed readily. Although, it's also possible that something else might have been brought up instead as an excuse not to pass the product. Frankly, it's also possible that had they been assigned another individual at that same NRTL it would have passed as well. But regardless of the solution, is the product any safer or more compliant because of how NRTL B handled the certification?
In the end, the instrument maker did in fact switch to another NRTL and they passed safety approvals without any issues. Of course, they had to pay the first NRTL for the time and aggravation as well as the NRTL they ended up using.
Case 2: Problems Within a Single NRTL Organization
A medical product company decided to use NRTL "C" to certify their new product for global sales. NRTL C has branches around the world. It's the same organization—just with different branches.
The medical product manufacturer developed its product in North America using a power supply which was designed in Europe. Then it submitted the product to a branch of NRTL C in North America for certification. As is customary during the certification process, the NRTL created a list of "things we need more information about" or that the customer simply must change. In this case, NRTL C took exception to the certifications of the power supply and would not accept them.
However, the medical product company quickly pointed out that those power supply certifications were from the NRTL C organization, so how could they possibly have an issue with them? It would be taking exception to its own work one would think.
The answer was that NRTL C Americas and NRTL C Europe are different entities, and the Americas branch would not automatically honor the certification of their European colleagues. In this case, the customer elected to pay NRTL C Americas to re-certify NRTL C Europe's work. It was paperwork only and no further testing was done. So, is the product safer or more compliant due to this?
Case 3: When It's Easier to Find a New Lab
Another medical instrument company submitted their product to NRTL "D" for approval. Here, the NRTL took exception to the type of plastic used in the product case. Their concern was not related to flammability, but rather the insulation barrier and conductivity of the plastic used in the chassis. Unfortunately, changing the type of plastic, the vacuum molding set-up and die, and associated things to modify this aspect of the design, especially at this late stage, would cost a great deal of money. This change would also add delays to the project launch, resulting in a loss of market share to the medical instrument company.
The solution in this case was to move to another NRTL, which passed the product to the same specifications with no changes made. Had the instrument company submitted their product to a different NRTL in the beginning, or possibly just been assigned to a different individual at NRTL D, they might have passed compliance testing with no problems.
Case 4: When the Lab Doesn't Test Appropriately
In this situation, a third medical instrument company was failing hipot testing with a power supply that had passed medical electronics standards with some margin. The maker of the power supply states they do so right on the product and offers documentation for same. But the NRTL doing the hipot testing was using ac testing and damaging the Y capacitors in the power supply in the process.
The standard allows for dc equivalent testing, and it was pointed out to the NRTL that all they were doing was damaging the Y capacitors and not measuring the actual safety barriers of the power supply. Nevertheless, they continued to test and damage power supplies, charging the customer for their time and of course damaging power supplies so that they could not be used after the destructive testing.
In this case, the power level was low, and the medical instrument company had chosen to embed the offline power supply in their product. However, because of the problem with getting the product to pass hipot, I recommended to the medical instrument company that they re-design the product to get all high voltage out and just have a low-voltage sealed connector on their product. Then they could use an external "wall wart" power supply with as many approvals and medical certifications as I could find at that power level.
The NRTL accepted the external power supply's certifications and stopped hipot testing. For some reason, this external power supply approach with a fully certified one was such that no testing was needed on the power supply and the medical product passed safety certification immediately using the same NRTL from start to finish. Was that necessary? The product in the end might have been safer or not. But the low-voltage approach was a better one as it passed the burden of passing hipot onto the power supply vendor, so I have mixed thoughts on this one.
Case 5: When the Lab Gives Good Advice
A customer decided to design their own power conversion in an industrial product and went to NRTL "E" for testing. The customer had made many mistakes in the design including not using bridge rectifiers which had safety certifications including those for flammability compliance. The NRTL flagged these issues and also objected to the X and Y caps and other items connected to the mains. The laboratory recommended that the customer simply use a commercial power supply that had all the necessary documentation and not try to build their own.
In this case, NRTL E did a good job because it educated the customer that they really should not be designing their own power supplies. Although it was a blow to their egos, they were not better at it than companies which design and build power supplies as their end products. In this case it I wondered if they had gotten another tester at NRTL E or used another test company, would they have passed the product? Would that have been the right thing to do? In the end, it was better that the medical company used a commercial medical power supply—whether they knew it or not.
Case 6: Some NRTL Reps Go Out of Their Way to Help
While working at a power supply company, I had once provided extensive information to NRTL "F" on a certain power supply that was being used by one of our customers in a medical product. That power supply was originally approved by another NRTL, so the agent at NRTL F was just doing the research to confirm the power supply's compliance. That done, the medical product was approved.
Sometime later, I was contacted again by NRTL F about their testing of another medical product from a different company, also our customer. It turned out this second customer was using the same power supply as the previously approved medical product discussed above.
Once informed of the test lab's previous experience with the power supply, the NRTL F representative informed me that he didn't need any more information. He would simply take the data he already had from the past product approval and use it for this second medical device customer.
Now that was class. Since the present medical customer didn't know about the power supply's history, the NRTL representative could have easily charged the customer full price and billed hours for learning about something they already knew and making it new all over again.
NRTL F did the right thing both times. They could have given the first customer a hard time because the power supply was originally approved by another NRTL. But they just confirmed the approval and accepted it. Then they could have charged the second customer for redoing the research, or even rejected the power supply's approval from another NRTL. But they did not do those things.
In both cases, they saved our mutual customers time and money. I hope the individual didn't get in trouble for being helpful, efficient, and using common sense. These days in most organizations, "following the process" is more important than results.
Case 7: Promises Made But Not Delivered
A scientific instrument company submitted a project to NRTL "G" who promised the customer a timeline for completion of the project to certify their product. The project was assigned to an individual at the lab who started to work on the project and sent the customer lots of questions to answer. The customer answered the questions and NRTL G went dark on asking for anything else.
So, it was assumed that the project was being worked on. It turned out that the employee at NRTL G left and the project was not reassigned. But this was just the beginning of the problems. It seems that NRTL G had a systematic problem with turnover, so the project would be handed off to a new representative several times. And every time a new person was placed on the project, a different set of questions was asked, and there was no mention of the questions asked by the prior employee. The project was new repeatedly.
This of course cost the company time and money and the solution in the end was that the scientific instrument company changed NRTLs. With compliance being handled by a different lab, the customer was served with a small list of questions, which they answered, and the product passed without further incident.
How to Avoid Safety Compliance Nightmares
What can we learn from all this? The system works sometimes and sometimes not. In some cases, the exceptions taken seem to be more about maximizing billable hours than about verifying safety and compliance. Sometimes this system gives you a better product, but often the equipment maker doesn't change anything on the product—lots of paper (or now electronic files) just get moved around and money changes hands.
So how can you avoid having to pay out a lot of money or wasting a lot of time? If your organization has an internal safety and compliance group and/or you can self-certify, that is often the best situation. Your internal team can collaborate with you early to avoid potential certification issues.
If you must go outside for compliance testing, keep in mind that the mindset of your NRTL partner might not be to help you achieve your goals in a timely manner. Don't believe for a second that all NRTLs are the same, they are not. You should interview them ahead of time, interview who they are going to have working on your project and give a "not to exceed" quotation for the project.
If they say they can't quote it until they have more information, then let them know you will supply the information needed to quote. Otherwise, you are giving them a blank check to have their way with you. If no exceptions are taken during the quoting process, why would they become an issue after the project starts? Well, that's because you were a prospect before and now you are a client customer—if the rules change after the fact, you are too far in.
Also ask for the background on the person doing the work for you. How many years do they have working on projects such as yours? How long have they been with the NRTL? If they will let you involve them early and often in the product development process, it may prevent problems later, as it becomes more expensive to change things as the project moves along the development pipeline.
You may think that since the person works at a big NRTL organization they must be competent, right? Well don't assume that. Ask to interview the person who is going to be doing the work and ask about qualifications, longevity, projects worked on successfully, etc. Interview them like you are interviewing a prospective employee. If you don't like the answers, request another person or find another NRTL.
Another tip is to choose sub-assemblies with compliance in mind. Do the equipment and components being selected meet all the usual necessary and customary compliance certifications with documentation available to back up claims?
Finally, talk to other customers of the NRTL being considered, ask for references, and call them—what has been their experience working with the lab? Do they stick to the set price or are they constantly finding reasons for billing more hours? Don't forget that selecting an NRTL and staff to work with is like interviewing a potential employee. You will potentially live with this decision for a long time, and they can cause delays and costs to spiral out of control such that the only way to fix it will be the application of more time and money.
Choose carefully and involve the lab early, keeping in mind that you are more likely to have a good result if you set clear expectations on both sides from the start. If you think that the nightmares described in this article cannot happen to you, consider that neither did any of the companies involved in these stories. By the time, these companies discovered their problems, they were too far into the compliance process to fix them easily and resolving them required much more time and money than they had expected to invest.
|Author: Kevin Parmenter
Director of Applications Engineering
Taiwan Semiconductor America
EnerHarv 2022 will bring together experts from around the world working on all technical areas relevant to energy harvesting, power management and its IoT applications. This non-profit workshop, organized and sponsored by the Power Sources Manufacturers Association (PSMA), will be held on the Centennial Campus of NC State University in the award-winning Hunt Library. The workshop will be hosted by the ASSIST NSF Engineering Research Center.
EnerHarv 2022’s vision is to create a focal point for experts and users of energy harvesting and related technologies to share knowledge, best practices, roadmaps, experiences and provide opportunities for collaboration to increase the uptake of such technologies. The workshop is targeted at a broad audience from industry and academia working on materials and devices for energy harvesting and storage, low-power sensors and circuits, micro power management, and their applications in powering IoT devices for health and environmental monitoring, assisted living, and monitoring of equipment and buildings. The workshop program will be divided evenly between lecture sessions, functional demonstrations, and interactive panel discussions with plenty of time reserved for networking and team-building prospects. More information on the workshop can be found at http://www.EnerHarv.com.
Mehmet C. Ozturk
Cornell Dubilier has brought its Illinois Capacitor brand capacitors to cde.com. Now engineers can view the entire portfolio of CDE and IC capacitors for power electronics applications on one site. This includes such specialized products as IC’s supercapacitors, conduction-cooled (high density resonant) capacitors, rechargeable coin cell batteries, and other new additions. CDE’s updated parametric search tools simplify the capacitor selection process as never before.
As Illinoiscapacitor.com has now been shut down, links to that site will be automatically redirected to cde.com. In addition to combining product data, the site’s Tech Center has been expanded to include additional engineering resources, such as application guides, capacitor formulas, tutorials, and a detailed glossary of terms.
CDE will continue to support all IC branded products, which are available from major distributors and the company’s representative network.
For more information, visit www.cde.com.
TDK Corporation announced today that subsidiary TDK Ventures Inc. invests in AM Batteries (AMB) to support the commercialization of their dry electrode coating technology that improves the manufacturing of lithium-ion batteries built on a bedrock of unmatched expertise in advanced chemistry, surface science, and precision additive manufacturing. AMB’s electrodes not only have the potential to save cost, but also offer a path toward fast charging, higher-energy density, and adaptability. AMB has early industry attraction to adopt this technology for pilot scale to mass production.
AMB has developed a novel additive Li-ion manufacturing technique by which the active materials (cathode/anode) are charged and sprayed onto metal foil current collectors, which are then processed to its final state to make batteries without the use of toxic solvent. This dry- coating method offers significant cost and energy savings over state-of-the-art “wet coating” procedures, providing a dramatic improvement to the sustainability of the overall cell making process. TDK Ventures' investment in AMB marks its continued focus on core technologies that catalyze broader decarbonization efforts via sustainable and scalable battery technologies.
“Our technology is extremely innovative and outside the box,” stated Yan Wang AMB Co-founder and CEO. “TDK Ventures’ proprietary knowledge and unique insights in the battery-manufacturing space helped validate our own technological progress. They also played a significant role in bringing a broad syndicate of financial, strategic, and OEM partners together by sharing their key techno-economic insights, thereby helping us assemble a world-class set of partners for our company.”
Riding the rising tide of EVs, the demand for lithium-ion batteries has never been higher - with an expected need for more than 2,000 GWh by 2030. With this significant manufacturing capacity demand, environmental and carbon footprint are under increased scrutiny. Current wet-electrode manufacturing techniques consume up to 50% of the total manufacturing energy of the entire battery, require significant factory footprint to dry the solvent, and increase the CAPEX required for manufacturing plants. One of the most fundamental problems for battery manufacturers today is refining manufacturing techniques. Refining manufacturing techniques to remove the solvent is one of the most fundamental problems for all battery manufacturers today in the consumer electronics, large scale energy storage, and EV markets.
During Tesla’s 2020 Battery Day last year, CEO Elon Musk said that dry-electrode technology is one of the most vital components for a step-change in the cost reduction of EV batteries; he also stated significant room for the technology’s maturation and improvement. Tesla acquired Maxwell Technologies in early 2019 with an eye on potentially commercializing their dry-electrode technology.
“AMB has engineered a three-step electro-spraying system that seamlessly aligns with the existing process flow of lithium-battery manufacturing, which is not the case in competitive solutions, putting them at the very forefront of the industry,” said Nicolas Sauvage, President of TDK Ventures. “In the future, we believe that battery manufacturers will not only differentiate on energy density, fast charge ability, or cost/kW, but also on the amount of CO2 emitted per the amount of energy stored, which is a measure of how sustainable one’s electrode manufacturing process is. This positioning is a whole new value proposition for next-generation battery manufacturers and EV OEMs that align with consumer needs.”
Eric Rosenblum, Foothill Ventures' Managing Partner commented: "The battery market for EVs is one of the world's most important markets, and this technology addresses two of the biggest issues: cost and sustainability. Dr. Yan Wang has proven himself to be one of the most successful inventors and serial entrepreneurs in the battery space, and we are also thrilled to partner again with TDK Ventures."
AMB closed its seed round of $3M in funding September 2021 with TDK Ventures and Foothill ventures co-leading the round. SAIC Capital (Tier I manufacturer), VinFast (Vietnamese EV OEM), Doral Energy-Tech Ventures (Israel Renewable Energy Company), Creative Ventures (financial VC firm from Silicon Valley) also participated in the round. In January 2020, AMB’s founders secured a $2.4M three-year research grant by the United States Advanced Battery Consortium (USABC), based on its strong foundational academic progress.
PSMA has announced the availability of a White Paper entitled “Energy Harvesting for a Green Internet of Things.” This seminal work is the result of a multi-month effort by a dedicated team of 28 international experts from a variety of backgrounds in academia and industry, led by Dr. Michalis Kiziroglou from Imperial College London and Dr. Thomas Becker of Thobecore Germany. The PSMA Energy Harvesting Technical Committee supported this work and is responsible for making the White Paper available.
The ubiquitous nature of energy autonomous microsystems, which are easy to install and simple to connect to a network, make them attractive in the rapidly growing Internet of Things (IoT) ecosystem. The growing energy consumption of the IoT infrastructure is becoming more and more visible and impactful. Energy harvesting describes the conversion of ambient energy into electricity, enabling green power supply of IoT key components such as autonomous sensor nodes. Energy harvesting could lead to a lower CO2 footprint of future IoT devices by adapting environmentally-friendly materials and reducing cabling and primary battery usage.
The key findings in the White Paper are as follows:
- energy harvesting is a key enabling technology for the green Internet of Things;
- this potential is demonstrated with several use-case studies;
- industrial adoption is reluctant despite positive costs-benefits and their life-cycle impacts;
- massive future deployment requires a concerted strategy in research and technology accompanied by disruptive industrial product developments and innovations.
The paper is available at no cost on the PSMA website Energy Harvesting Technical Forum at https://www.psma.com/technical-forums/energy-harvesting/whitepaper.
PSMA is a non-profit professional organization with the objective of enhancing the stature and reputation of its members and their products, and improvement of their technological power sources knowledge. Its aim is to educate the entire electronics industry, academia, government, and industry agencies as to the applications and importance of all types of power sources and conversion devices.
The Energy Harvesting Committee is one of 12 committees within PSMA that focuses on particular power electronics technologies (from materials to devices and systems) and/or applications. The committee is planning the 2022 EnerHarv Workshop at NCSU in Raleigh, NC. For more information, visit www.enerharv.com
The PSMA Industry Education Committee and IEEE PELS will be sponsoring a series of seminars for young professionals designed to provide them guidance in their professional careers in the power electronics industry. The series will include in-person, webinar and hybrid events. The seminars will cover a range of non-technical topics that are vital to advancing the careers of engineers starting in the power electronics industry and will be made available at no cost to attendees.
The first of these seminars will be held in-person in conjunction with the 2021 Power Supply on Chip (PwrSoC) Workshop from 5:30 PM to 6:30 PM on Sunday October 24 at the Singh Center for Nanotechnology on the campus of the University of Pennsylvania in Philadelphia PA.
This session is open to all in-person registered attendees of the 2021 Power Supply on Chip workshop and will address the importance of social networking and how to network or connect with people more effectively. Students, young professionals, and even seasoned professionals will gain valuable insights and guidance on making meaningful connections with others.
The presenter and facilitator for this session is Ada Cheng. Ada Cheng was an electrical engineer at Motorola for 11 years before transitioning into a market analyst role at Gartner Dataquest. Consequently, she had to learn how to network quickly. As a result of networking, Ada served over 13 years on the APEC committee in various invited roles. Now as a market consultant with AdaClock and Anagenesis, she shares practical advice and tips for engineers to network effectively as part of their careers.
We look forward to the inaugural seminar of the series and encourage all those who will be attending the seminar on Sunday October 24 to bring their business cards – you will be glad that you did.
For more information and to join the mailing list to receive information on future seminars, visit the PSMA Education Forum. If you have any suggested topics to be included in the series and/or are interested in presenting a seminar, please contact the PSMA Office at firstname.lastname@example.org.
An article with additional information on the series will be included in the next issue of the PSMA UPDATE.
he 2021 PSMA Planning Meeting was held virtually on October 19, 2021. The Annual PSMA Planning Meeting addresses the future direction of the organization and focuses on the current major issues in the industry. The objective is to identify programs for the next year that will continue to bring benefits to the membership. While it was disappointing not to be able to see everyone in person, the online format did create the opportunity for a strong showing with 40 attendees.
PSMA Chair Mike Hayes welcomed all attendees and briefly reviewed the mission of the Association, the Vision for 2020-2025 (and beyond). the progress to better define and strategically align the Executive Committee and the many activities to minimize the financial impact of the Covid storm to minimize the financial impacts.
Mike summarized the general health and status of the organization and recognized the outstanding contributions by the Technical Committees, highlighting the newly formed Energy Storage Committee and the resurrection of the Industry-Education Committee. There have also been continued efforts to increase the relationships and cooperation with other key industry organizations – most notably with IPC, iNEMI, PELS, EPSMA and CPSS.
Mike ended his presentation with a discussion of some next steps currently underway to maintain the momentum of the key activities to maintain the position and stature of the Association for the benefit of our member companies and the power industry.
Following Mike's presentation, there were presentations from each of the other Executive Committee members.
Tim McDonald, Secretary/Treasurer, presented a 10-Quarter financial forecast for October 2021 – March 2024, including three scenarios – best case, nominal case, and worst case. The Financial Forecasts highlighted the need to identify New Revenue Opportunities as the Association works to maintain an acceptable financial position despite the lost revenue and financial obligations from events that were canceled or held virtually due to the COVID-19 pandemic. Some of the new revenue opportunities being considered include Power Technology Roadmap Underwriting, increasing membership dues, and hosting paid webinars.
In summary, the forecast supports that the Association will remain in good financial position assuming modest revenues from planned workshops and symposia in the coming year. Although the current financial position does limit available funding for Special Projects, through a combination of controlling expenditures and increasing revenues, the forecast projects that in the next 12-18 month timeframe there will be opportunities to fund a limited number of Projects that promise to bring value to the membership and the industry.
KPIs-Metrics that Matter
Trifon Liakopoulos, PSMA Vice President, discussed the work underway to identify the KPIs – Key Performance Indicators - that are actionable and tied to the business and financial goals of the organization. KPIs are metrics that matter since they will provide information on the success of current activities, identify opportunities to improve the activities of the Technical Committees, improve the effectiveness of the website, workshops, special projects, and webinars, and enhance efforts to attract new membership. This is a work in process with the initial focus to identify and plan for the infrastructure (people, web management and responsibilities) that will enable us to gather the information to improve the performance and effectiveness of the organization.
Power of the Pillars
Fred Weber briefly reviewed the Power of the Pillars and updates since the 2020 Planning Meeting. He highlighted the value of collaborations, including both committee collaboration within PSMA and collaborations with other organizations. Other themes discussed included increasing PSMA's visibility with companies in industries that are currently underrepresented, such as automotive; increasing member participation; and identifying revenue opportunities.
Following each of the Executive Committee opening presentations there was a brief Q&A including questions and suggestions from attendees. To keep the meeting on schedule, Fred took notes on these discussions for inclusion in the Planning Session later in the agenda.
There was a report from each of the PSMA committees that summarized their accomplishments over the past year and focused on ongoing programs and projects for 2022. Nine of the committees have submitted proposals to organize Industry Sessions at APEC 2022 and all technical committees are supporting the 2022 Power Technology Roadmap effort. The committee reports each included information on how their activities align with the Four Pillars and strategic focus on IoT, smart mobility and storage.
- Pierre Lohrber, Capacitor Committee
- Co-Chair, reviewed the mission of the committee and highlighted the current activities to interact with other Technical Committees - specifically the Magnetics, Energy Management and Energy Storage Committees. Pierre recognized Wilmer Companioni who recently stepped down as Co-Chair and welcomed new Co-Chair Andrew Mikulski.
- Energy Harvesting Committee Co-Chairs Mike Hayes and Brian Zahnstecher reviewed the mission and recent activities of the committee. The committee recently published and released a seminal White Paper which was authored by 28 experts from several countries reviewing the technology and challenges that will bring Energy Harvesting to a significant market presence. They are also planning EnerHarv 2022 to be held at North Carolina State University.
- David Chen, Energy Management Committee Chair, reported that the committee has grown to 32 people on the distribution list with 12 active members that participate in monthly meetings. David recognized Ed Herbert who has stepped down as committee Co-Chair. The committee is looking for a co-chair to assist in the planning and future activities. The committee continues to support the Energy Efficiency Data Base (EEDB) and the Safety and Compliance Data Base (SCDB).
- Energy Storage Committee Co-Chair Edward Schneider reported that the PSMA Board accepted the Energy Storage Subcommittee as a standalone Technical Committee earlier this year. The committee continues its cooperation with the Capacitor, Energy Management and other technical committees since energy storage is recognized as a critical technological focus for the overall power sources industry.
- John Horzepa presented a report prepared with Gerry Moschopoulos, Committee Co-Chair. The committee continues to support the student attendance program for APEC and the posting of Student Resumes on the PSMA website. In recent months, the committee membership and active participation have increased resulting in several new initiatives that are being considered. A Young Professionals Seminar Series is being planned together with IEEE PELS as a series of in-person, hybrid and virtual events that will focus on the needs of students and young professionals to help them develop the technical and interpersonal skills that will enable them to succeed in their careers. The committee is also planning a program providing an introduction to the PSMA Committees during APEC 2022.
- Magnetics Committee Co-Chair George Slama reported that the committee is planning its seventh annual workshop at APEC 2021. George recognized Steve Carlsen who recently stepped down as Co-Chair and welcomed new Co-Chair Matt Wilkowski.
- Ada Cheng, Marketing Committee Member, reviewed recent activities of the committee. The committee is again supporting the PSMA Passport Program at APEC 2022. The committee has also been active in identifying and supporting New Revenue options including reexamining increasing the levels of membership dues and identifying opportunities for attracting new membership. The committee is currently looking for new co-chairs to assist in the planning and future activities.
- Brian Narveson, Packaging and Manufacturing Committee Co-Chair, reported the committee has been very active in the past year, including supporting 3 workshops. The Covid-19 pandemic impacted the planning for all these events. The 3D-PEIM 2021 Symposium was held in Osaka Japan in June as a full virtual event and was both a technical and financial success. PwrSoC and IWIPP were both postponed from their originally scheduled dates and each held successful free corridor webinar series. PwrSoC 2021 is planned as a live hybrid event in late October.
- Power Technology Roadmap Committee Co-Chairs Dhaval Dalal and Conor Quinn reviewed the timeline for the 2022 Roadmap and reviewed the webinars that have been held to date and those that are currently scheduled. He thanked the PSMA Technical committees for their contributions and asked that they continue their efforts to identify webinar topics and presenters for the remaining slots in November and December for the upcoming Roadmap. Dhaval also reviewed the PTR Webinar Underwriting effort to identify and signup underwriters for 2021-2022 to generate additional revenue for PSMA.
- Reliability Committee Chair Brian Zahnstecher reported that the continues to look for a co-chair to assist in the planning and future activities of the committee. He reviewed the growing relationship with IPC and the planned collaboration in the generation of a new software reliability standard. The committee is currently working with EPSMA to schedule a webinar on the EPSMA Component Lifetime Prediction White Paper.
- John Horzepa reported that the Safety and Compliance Committee continues to seek additional membership and volunteers to serve as co-Chairs and requested the group to suggest individuals from their organization that may be interested in contributing to the work of the committee. Committee members share information and updates through regular email blasts but has not been holding regular meetings due to lack of leadership and member participation. In the past year, the committee sponsored a very successful webinar on EMC Basics presented by RECOM Power and hosted by David Chen and has a second webinar planned later this year. Together with the Energy Management Committee, the Safety and Compliance committee has supported the Safety and Compliance Data Base available on the PSMA website.
- Co-Chair Tim McDonald reported the Semiconductor Committee continues to be very active. He recognized Tirthajyoti Sarkar who recently stepped down as Co-Chair and welcomed new Co-Chair, Jaume Roig. For APEC 2022, the committee has again proposed 4 Industry Sessions. The committee is working to further align its activities in support and collaboration with other PSMA Technical Committees, including identifying industry-relevant topics for a future tutorial.
- Fred Weber, Transportation Electronics Committee Co-Chair, reported that committee remains very active with 12-15 people attending the monthly meetings. The committee continues to seek additional members from companies in the Automotive industry segment and continues their interaction with National Labs and other organizations involved with R&D projects in support of vehicle and transportation technologies.
There was a short break after the Committee Reports, and when the meeting reconvened, Fred Weber, PSMA President, led the 2021 planning exercise. During the first half of the meeting, he tracked the ideas brought up in the reports and discussion and split them into quick "Tiger Team" actions and long-term strategic issues. He then opened the brainstorming session by reviewing the Four Pillars (Build on Strengths, Become more Applications Oriented, Integrate Metrics, Engage with Stakeholders) and inviting everyone at the meeting to suggest ideas for the coming year.
Fred then briefly reviewed the completed and ongoing activities of the Tiger Teams over the past year. Building on the plans of the Technical Committees and Executive Committee as presented in the meeting and considering the comments by attendees, Fred identified and listed a number of new Tiger Team initiatives for the coming year. Each initiative was discussed to identify suggested champions, the support groups and target due dates.
Summary and Close
Mike Hayes thanked the attendees for their inputs and participation. PSMA members can view the minutes from the Planning Meeting in the Members Only section of the PSMA web site.
IPC in cooperation with PSMA is developing a new standard on the "Specification for Firmware Design and Test Requirements for Power Subsystem Assemblies". The proposal for this standard is based on the "PSMA Power Supply Software/Firmware Reliability Improvement Report." This report was written as part of a special project sponsored by the PSMA Reliability Committee.
We are seeking members from PSMA and the greater power electronics community to join this effort. Topics that are proposed to be a part of this standard include:
- Firmware design requirements including basic function, error handling, reliability, performance, etc. This will cover basic architecture and design around that architecture as well as upgradeability. A section to be included on understanding intended application environment.
- Firmware test/qualification requirements to verify that the design elements are operating at minimum level. Sections would include testing to verify all critical design and application requirements. It will address exerciser code, unit test and integration topics.
- Firmware security for protecting against internal threats and external attack. Sections to include library verification, access to source code, physical security, plugging into the IT/OT network, user logging and tracking, virus mitigation, external access security, update/upgrade security, etc.
We are in the process of forming the committee to start drafting this standard and are seeking members interested participating and/or leading the development of various sections to be included in the document. This is intended to be a requirements standard that can be used to define expectations for firmware design, test, and security in power assemblies and could be considered the start of a family of standards that complement the current IPC-9592B standard. Please contact any of the following people if interested.
Thank you for your consideration. We look forward to hearing from you.
riends of PSMA introduces readers to organizations that PSMA has cooperative relationship with to better serve our respective memberships and the international power electronics industry. If you have suggestions on other industry organizations to consider or ways that we can improve our current relationship with other industry associations, we would be delighted to hear from you.
In this article we introduce you to the The European Power Supply Manufacturers' Association (EPSMA).
In the year 2020, the EPSMA celebrated the 25th anniversary of its founding. It was formed from a group of European power supply manufacturers who were participating in a continuous power market survey, organized by IMS, now IHS Markit. The data from the companies was anonymized, but the group made connections with each other and saw an advantage in forming an association for their mutual benefit. IHS agreed to act as the secretariat for the group and it was formally registered as a 'European Economic Interest Group' (EEIG) in 2002. This status allowed companies who were often competitors to meet as a 'trade association' to represent the interests of their members to national bodies and to promote European power supply manufacturers overall. To be able to monitor and influence European standards relating to power supplies, the EPSMA became a CENELEC liaison organization, affiliated with technical committee TC 22X, which is responsible for standards relating to power converters. Some EPSMA members are in fact already members of TC 22X. IHS relinquished the secretariat service in 2015 and the function is now within the EPSMA organization.
Some of the initial work by the EPSMA was related to the protection of the European industry from product and component 'dumping' from the far east which was creating an unfair market with items that were not necessarily meeting acceptable quality standards. The EPSMA identified related products and informed the authorities. Another area of work was an effort to influence and mitigate the effects of the original power factor correction (PFC) requirements, that had been imposed on the industry with little warning.
EPSMA membership originally was limited to power companies headquartered in Europe, but with the globalization of the industry, this was relaxed and any power supply manufacturer or supplier to the industry can join as a full member if they have at least one full-time employee in Europe. There is also an affiliate membership category which typically includes educational establishments such as universities. The EPSMA is controlled by a management committee of around twelve members which meets four times each year, either in person or by teleconference. There is also a technical committee (TC) consisting of experts from member companies, which meets to discuss technical developments in the industry and inform the membership. The TC also generates in-depth technical documents, typically related to standards, for the guidance of members. These documents are available for non-members to purchase. The most popular over time has been the EPSMA's analysis of the PFC or 'harmonic emissions' standard with specific guidance on how to comply. This was updated in 2018 to include the most recent requirements. Other documents published include guidance for compliance with medical, rail, telecomms, DIN rail and hazardous location safety standards.
The TC has also published papers on the implications of the RoHS, WEEE directives and general power supply design guides on 'Accurate Efficiency Measurements', 'Lifetime Prediction', 'Reliability Prediction' and 'Embedded Software verification and Validation'. Some of these documents are free to download for non-members and a full list, including abstracts of 'members only' documents are available at www.epsma.org/technical-publications. The current work by the TC is focused on generating a guidance document about 'Over-voltage Categories' and their implications on power supply design.
As of today, the EPSMA has around 25 members including all of the main European power supply manufacturers. Six universities are affiliate members as is one of the European test houses. Four of the founding members remain active in the association and new members join at a steady rate. The website www.epsma.org is the portal for information on the activities of the EPSMA with member news and product press releases, information about latest publications, member job vacancies and a quarterly newsletter. There are links on the website to industry resources and indeed to the PSMA. For more information about membership or any other aspect of the EPSMA, please contact: email@example.com.
Provided by Paul Lee, EPSMA Secretariat
TDK Corporation presents the new, powerful and intuitive CLARA tool (Capacitor Life And Rating Application) for calculating and selecting EPCOS and TDK film capacitors for PCB mounting. The tool offers a versatile parametric search functionality. This includes a search for capacitance, voltage range as well as for rated voltage, RMS and peak current, temperature, maximum dimensions and volume, approvals, reference standards as well as typical applications.
By clicking just once, the performance of up to four capacitors can be simulated under application conditions. This is displayed in a clear table, which may include the following parameters, for example: operating temperature, DC voltage, AC voltage, peak current and expected service life. Furthermore, safety tolerances are specified allowing developers to adjust the configuration in line with their specific requirements. Moreover, a warning is issued if the permitted capacitor parameters are exceeded.
Application conditions, including personal notes, can be stored for future use. STEP files and SPICE simulation data are available for the majority of capacitors. CLARA is linked to the TDK Product Center. The selected capacitors can be easily ordered from there by means of service distributors. The new tool is available for developers at:
he Energy Harvesting White Paper Committee is preparing a White Paper on Energy Harvesting elucidating the enormous opportunities of the technology despite a reluctant adoption in some industries.
Although Energy Harvesting methods and devices have reached a credible state-of-art, relatively few devices are currently commercially available and off-the-shelf harvester solutions often require an extensive adaption to the envisaged application. A synopsis of typical energy sources, state-of-the-art materials and transducer technologies for efficient energy conversion, storage and management encompasses a wide range of successful research results. But developing power supplies for actual applications reveals their strong dependence on application-specific installation requirements, power demands and environmental conditions resulting in a less extensive portfolio of successful system integrations.
The industrial challenges for a massive spread of autonomous sensor systems are manifold and diverse. Reliability issues, obsolescence management and supply chains need to be analysed for commercial use in critical applications. On this front, the gap between currently available solutions and use-case scenarios is analysed from the perspective of the user. The white paper then proceeds to identify the key advantages of energy autonomy in environmental, reliability, sustainability and financial terms.
Energy harvesting could lead to a lower CO2 footprint of future IoT devices by adopting environmentally friendly materials and reducing cabling as well as battery replacement. Further research and development is evidently needed to achieve a technology readiness levels acceptable for the industry. From this discussion, this white paper will propose a future research and innovation strategy for industry-ready green microscale IoT devices, as a key and seminal initiative to provide useful information to the different stakeholders involved, encourage more interaction between them and deliver industry ready solutions.
n the quest to increase power utilization efficiency and to achieve the computation of more data in smaller spaces, the computing industry investigated alternative solutions to forced air-cooling. Cold wall and baseplate cooling methods, helped by liquid or gas exchangers have been used for decades and from a laptop, datacenters and on to radio base stations, a well-established technology to extract calories from dissipating components has been achieved. The technology worked well, but to jump from 40kW per rack to 250kW and more, even that technology reached its limits.
How to get more computing power from a datacenter with safety and efficiency has been the concern of many engineers, and the idea to get the full benefit of liquid cooling by immersing heavy computing systems into fluid became an interesting option. After more than 10 years of experimentation, business cases and trials, where does that industry stand in 2021 and how will power supplies adapt and develop to accommodate that technology?
From fish-tank to super high density datacenter
If you are a fan of online gaming requiring huge levels of computing power, you may remember PC conventions where geeks presented oil immersed computers in a fish-tank (Figure 01). Anecdotal as it may seem, beginning in 2005, the idea to benefit from deep liquid cooling technology has been explored by the gaming community but the biggest interest for that technology emerged from Bitcoin mining requiring massive computing power.
At the origin of Bitcoin mining, many companies took advantage of the cold Nordic environment and the locally produced renewable hydroelectric energy to setup datacenters. Nordic countries began many projects to support those initiatives. One example is the Swedish project, 'The Node Pole' promoting an abundance of stable and competitively priced electricity from renewable energy, inviting datacenter operators to benefit from this specific environment.
Many leading companies launched datacenters in Nordic countries, e.g. in Boden, Sweden. We could mention the Bitcoin company KnC Miner, who in 2014 opened a 10 megawatt data center filled with high-powered computers mining for cryptocurrency, capitalizing on the benefits of hydroelectric power and natural cooling. Although the source of energy powering a Bitcoin farm was renewable, nonetheless the energy dissipated was lost and concern was emerging regarding 'Energy Utilization'. Many Bitcoin mining datacenters all over the world were operating in huge halls, with thousands of computing units cooled by forced air, without any heat recycling (Figure 02).
While Bitcoin mining centers operating in Nordic conditions could 'get by' using forced air cooling, the methodology was definitely not a long term solution, and where massive computing units operating in the rest of the world - and not benefiting from natural cold air - it was not a solution at all. In any case, considering the environmental aspect and impact, wasting energy became a major concern and even in Nordic countries local communities placed high demand levels on datacenters to improve Power Usage Effectiveness (PUE) and to optimize and re-use calories produced during the computing process, for example to heat water for public usage.
Besides Bitcoin mining, the growing demand for mass computing architecture for simulations and future networks of autonomous vehicles motivated datacenter operators to consider alternative methods to deliver extremely high computing power in smaller spaces with a PUE close to ONE. The idea to immerse the heavily computing parts of datacenters in fluid grew within the engineering community, with functional systems being tested in 2010.
The road for immersion cooling was opened!
When Bitcoin meets Big Data
We could name many experiments performed all over the world to design immersed, high computing power machines in fluids, but it's worth mentioning the 1.4MW container data center and its 240kW flat racks launched by the Hong-Kong based company Allied Control (now LiquidStack) and rewarded with the 'Best Green ICT Award' in 2014 (Figure 03).
From the first generation launched in 2012 to the third generation launched in 2015, cooperating with 3M under a project named 2PIC (2-phase Immersion Cooling), Allied Control increased the Total Watts Per Square Foot from 0.25kW to 3.23kW while maintaining a Power Usage Effectiveness (PUE) of 1.02. This has been made possible by optimizing the immersion cooling technology with the 3M coolant Novec 7100.
Presented at many conferences, e.g. Open Compute Project Summit (OCP Summit), immersion cooling offers unprecedented benefits in terms of performance. As shown in Figure 04, the power density per rack can increase from 40kW to 250kW (and more), the computing power from 10kW to 100kW per square meter, and the energy used for cooling to reduce from 2.0 pPUE (partial Power Usage Effectiveness) to below 1.02 pPUE.
In addition to improving performance, immersion cooling is also considered by datacenter managers as a possible solution to reduce the risk of fire. We are all able to recall the fire at the French OVH datacenter in Strasbourg and the collateral damage that impacted their customers. Despite all caution and measures in place to prevent a fire, the increased power density of existing datacenters cooled by conventional methods remains a high concern for datacenter managers.
The dielectric coolants used in immersed datacenters have a dielectric strength that's thousands of times higher than air, so even if there's a short circuit in the coolant, there's no spark or ignition, which clearly greatly reduces the risk of fire. As well, immersed data centers are using a very limited number of fans, mainly used outside the computing environment in the heat exchanger.
All considered, immersed datacenters have lots of benefits and following on from Google, Alibaba and many others, the recent announcement from Microsoft to use two-phase immersion cooling in its Quincy, Washington Azure datacenter confirms the demand for Big Data computation taking over from the original Bitcoin experimentation phase.
Making datacenters more powerful and better in Power Usage Effectiveness is great but is cooling working and what will that mean for power supplies manufacturers?
SLIC and TLIC!
Two technologies are commonly used for immersion cooling: Single-phase Liquid Immersion Cooling (SLIC) and Two-phase Liquid Immersion Cooling (TLIC). Both technologies make it possible to achieve more than 200kW per rack with impressive PUE. The decision to use one or another technology depends on operational conditions and best practices as applied to specific industries. A lot of literature has been published on both, but in simple terms this is how it works:
Single-phase Liquid Immersion Cooling (SLIC)
Single-phase immersion cooling (Figure 05a) servers are usually installed vertically in the container and cooled by a hydrocarbon-based dielectric fluid that's similar to mineral oil, as was used by the gaming geek in the early days. The heat is transferred from the dissipating components to the coolant, which is then cooled via a heat exchanger in a cooling distribution unit (CDU). Single phase is very simple to operate and maintain. Beside hyperscale datacenters (Figure 05b), SLIC is the preferred solution for industrial computing systems operating in harsh environments requiring a very high level of safety.
Two-phase Liquid Immersion Cooling (TLIC)
In a two-phase immersion cooled system (Figure 06a), servers are immersed inside a bath of specially engineered fluorocarbon-based liquid. Because the fluid has a low boiling point (often below 50 degrees C vs. 100 degrees C for water), heat from the servers easily boils the surrounding fluid. The boiling of the liquid causes a change of state from liquid to gas, thus giving two-phase immersion cooling its name. The vapor is then condensed back to the liquid form via water-cooled condenser coils that are integrated into the top of the sealed racks. The condensed liquid drips back into the bath of fluid to be recycled through the system (Figure 06b).
Power to Immersion
The vast majority of datacenter equipments are powered by a front-end rectifier converting the AC voltage to 48V DC. Some are using a High Voltage DC (HVDC) distribution (e.g. 400 VDC). In the case of immersed equipment, the power supplies are often outside the tank and power supplies are off the shelf, however a number of highly integrated, high-density computing units are integrating the complete power solution.
Originally used in harsh environments where safety is important and cooling is complicated, immersed electronics has been in practice for many years. With the high demand for small networks with high computing capacity, the development of a new generation of highly integrated, immersed servers began, including the AC/DC power supply (Figure 07).
Although most of the power supply components are compatible with the different coolants used in SLIC and TLIC, power designers must carefully select electrolytic capacitors. Electrolytic capacitors are designed to sustain humidity, however their sealing capsule properties can be affected when permanently immersed. Because operating such a capacitor in an immersed conditions may be outside its normal specifications, it is important to simulate, test and verify capacitors' life time when immersed for deployment as such.
Another important parameter to take into consideration is thermal conditions, which in the case of a liquid coolant is very much different to that when operating in air conditions. In both cases, by circulation in the case of SLIC, and evaporation in the case of TLIC, the calories are evacuated from dissipating components much faster than in air. In some components such positive temperature coefficients (PTC) are temperature-dependent and in the case of immersed applications the gradient between low and high temperatures is much lower. Power designers must take this into consideration.
Coolants have high dielectric properties and there is no problem in operating high voltage switching topologies in immersed power supplies, although it is important to maintain a high physical isolation e.g. the use of a conformal coating to prevent corrosion from electrolyte effect that might happen when immersed in fluid.
Most of the layout principles used in air-cooling apply in immersed applications but it is important to make sure the fluid circulation is optimized within the power supply.
Last but not least, when operated in immersed conditions temperature measurement can be a challenge. Although conventional temperature sensors are often used with specific coupling to the dissipating components, other types of monitoring by digital measurement are often used instead. Also, techniques such as ripple and noise envelope analysis help to monitor the overall performance and to apply preventative maintenance when parameters are outside critical limits.
What's the next step?
What was started by gaming geeks immersing their computers in fish-tanks, and now to hyperscale massive computing datacenters, the immersed computing world is aimed to grow fast. The outbreak of COVID-19 is boosting Datacenter service demand and also new technologies such as autonomous vehicles, and 5G in its early stages. SLIC and TLIC will continue to improve performance levels, as will power supplies manufacturers working on highly efficient topologies using Wide Band Gap semiconductors (SiC and GaN). After 10 years of experimentation and local initiatives, the world of immersed computing is opening up nicely.
Power designers love a challenge and developing multi kilowatts immersed power supplies is a challenge they cannot resist.
he International Electronics Manufacturing Initiative (iNEMI) and the Power Sources Manufacturers Association (PSMA) have signed a memorandum of understanding (MOU) to collaborate and share information. The two organizations will continue to partner in key areas such as roadmap development and anticipate co-hosting technical webinars for benefit of the members of each organization and industry at large.
"iNEMI has had a long working relationship with PSMA, particularly in the area of roadmapping, and we hope to further expand our interaction to the mutual benefit of our respective memberships," said Shekhar Chandrashekhar, iNEMI CEO.
"All electronic assemblies need a power source, all power sources require expertise in interconnect, packaging, assembly, manufacturability and testability," said Mike Hayes, PSMA Chair. "The synergies between our organizations are obvious, and we look forward to building further our collaboration with iNEMI especially in educating, guiding and cross connecting our respective
hen in 1900 Max Planck deduced the relationship between energy and the frequency of radiation, his theory marked a turning point in physics and inspired up-and-coming physicists such as Albert Einstein. Few could have seen the implications of that discovery to the medical world.
From Max Planck to Tattoos
From Planck's discovery it was another 60 years of publications, inventions and innovations up to March 22, 1960 when two researchers at Bell Labs, Charles Townes and Arthur Schawlow, were granted US patent number 2,929,922 for the optical maser, now called a LASER (Light Amplification by Stimulated Emission of Radiation) (Figure 01).
2020 marks the 60th anniversary of the birth of LASER technology, it is also the anniversary of the first application in the medical field.
May 16, 1960: Theodore H. Maiman constructed the first laser using a cylinder of synthetic ruby measuring 1cm in diameter and 2cm long, with the ends silver-coated to make them reflective and able to serve as a Fabry-Perot resonator, using photographic flash-lamps as the laser's pump source. In 1962 a dermatologist named Leon Goldman experimented with a version of the Maiman ruby-laser to remove unwanted tattoos. In fact it is fair to say that Maiman's and Goldman's inventions and discoveries have contributed to one of the most popular uses of the medical-laser in the year 2020 - to remove unwanted tattoos (Figure 02).
If removing tattoos seems anecdotal, from that early application medical lasers have found their way into a wide variety of medical applications and without naming all, there are many examples of laser treatments in ophthalmology, oncology and other forms of surgery that we have all either benefited from or heard about.
When a power supply makes light emission possible
If the nature of the laser source is specific to the targeted treatment, i.e. generating light emission in the range of 193 nanometers (Excimer ArF) to 10.600 nanometers (CO2) (Figure 03) and pulses from 5 nanoseconds to 1 millisecond, they all have something in common - a power supply.
A function of the final application, each type of laser requires a different type of power supply which can vary from a current generator for continuous-wave diode laser, to complex power solutions in the case of gas-lasers or lamp-pumps using flash-lamps as a light generator.
We could probably identify as many power supplies as there are types of laser used in the medical space, although as a power supply manufacturer we simplify it to two:
Powering LED lasers
Originally limited in their power, diode lasers were not very common in medical applications, however with the development of a wide range of diodes generating wavelengths from 405 nanometers to 2200 nanometers, they become popular in the field of photodynamic therapy where the wavelength is more crucial.
As it is for other applications using LEDs (e.g. lighting) the power supply is often defined as an LED Driver. Used both in the new generation of solid-state lasers or as a generator as such, laser LED drivers require particular attention to the stability of the current and compensation of the energy delivered in terms of the temperature of the LED element. Modern current generators for LED lasers are based on digital technology with an input/output (I/O) interface making it possible to monitor and control the power supply to meet application requirements. Using predictive algorithms the power-stage can be programmed to operate safely and to deliver the specific energy required by a single pulse.
An LED laser could operate in the range of few milliwatts to more than 100 watts when using an LED matrix such as the ones used in LED solid-state pump-lights. With the development of supercapacitors, LED drivers for lasers often use them as energy storage. In such cases the power supply includes special circuitry that controls the energy stored in the supercapacitor to optimize, cycle-by-cycle, the level of energy delivered to the load.
Seen from a power supply designer's viewpoint, powering and LED laser applications are very similar to conventional current generators, which is not the case when designing power solutions for gas lasers or lamp-pumps using a discharge tube.
Powering gas and high energy solid-state lasers
Gas and high-energy solid state lasers use flash-lights or discharge tubes that require high voltages to generate the necessary energy levels needed to initiate the 'pumping process'. In this type of application the design of the power supply requires specific knowledge in high voltage switching and energy storage.
Lamp-pumped solid-state lasers and gas-laser power supplies have complex specifications, requiring two elements: a power supply converting the AC line voltage to the high voltage required by the emitting element, and a high-voltage capacitor energy bank for energy storage. Voltage will depend of the level of energy required to activate the pumping, but in conventional medical applications it is often between 600VDC and 3,000VDC.
Similar to your flash camera, the power supply charges a capacitor, which then delivers the energy to the flash lamp. However, while we can accept a small delay in charging the capacitor of our personal camera, in the case of a medical laser the energy needs to be available without delay, requiring a capacitor-bank to store high amounts of energy.
For power designers not used to dealing with high energy transfer topologies, it can be difficult to estimate the size of the energy envelope and preferred control method to optimize the power stage.
The required output power needed for lamp-pumped solid-state or high-powered pulsed-excimer lasers is usually given in terms of joules per second, which is a function of charge time, repetition rate, output voltage, and component characteristics. During a charge-discharge cycle, the rate of change in voltage is not constant, which differs very much from conventional applications where usually the peak-current and charge rate are pretty well defined. Designing such types of power supplies requires very close cooperation with the equipment manufacturer to test the power solution in real conditions.
It is very common for medical laser manufacturers to split the power solution into two parts. These are the power supply itself (Figure 04) and the high-voltage capacitor bank, which for safety reasons could be in a sealed tank.
In terms of technology, modern power supplies use digital control techniques, not only improving efficiency but in the case of medical lasers, also improving the reliability of the equipment due to its operating principle being based on pulsed energy which is known to be stressful for electronic components. As presented previously in the LED laser power solution part of this article, using digital control offers huge benefits in terms of energy management. It is possible to control the power unit to a single bit and to adjust all parameters cycle by cycle. For example during surgery the surgeon could request more power or longer pulses for tumor ablation. Controlled by the embedded computer, the power supply can be programmed in between two pulses to change the charging voltage and/or the amount of energy required by the emitting element.
What else should power designers consider?
Safety - There is no doubt that dealing with high voltages and significant amount of energy requires close attention to safety. Usually built into a final equipment, obviously the power supply must comply with overall safety and environmental regulations, but during the design process power designers must pay special attention to all risks related to hazards inherent to high voltages.
Risk - Regarding power supplies included in final equipments and not medical equipment as such, certain customers are requiring a full risk assessment analysis e.g. ISO 14971, which must be considered from day one.
EMI - High-peak energy switching generates electromagnetic emissions and line disturbances which may interfere with other medical equipment. Filtering and power factor correction requires special attention during the design phase to not only comply with standards and regulations at the time of certification, but to take cognizance of the aging of filtering components e.g. electrolytic capacitors during the all life time of the equipment.
Noise & thermal – In addition to local regulations, hospital, medical and para-medical institutions are requiring electronic equipments to operate without audible noise. Considering that laser equipment includes a number of dissipating elements, forced cooling is often required. To achieve good cooling with the lowest audible noise, manufacturers are using large fans rotating at low speeds to cool down their systems. For safety, capacitor-banks and power supplies are housed in sealed boxes, limiting cooling to conduction through the chassis. This is an important point to consider during the design of power supplies for medical lasers.
How can new power technologies benefit medical lasers?
For many years the size of a power supply for medical laser use hasn't been a real concern - but things are changing. Medical laser manufacturers are considering a new generation of 'portable' lasers for homecare and to increase the mobility of medical services. Research to develop more powerful, and with combined wavelengths LED lasers are showing good progress. Operational control is easily performed on a tablet (no more built-in displays) but of course parts of the equipment will require a serious diet to achieve portability.
In the case of LED lasers, supercapacitors based on nanotechnologies are offering impressive capacity levels to store high energy and together with the use of Wide Band Gap semiconductors e.g. Gallium Nitride, Silicon Carbide, the size of the power supply could be shrunk by a factor of x3. This is very promising and I have no doubt that LED medical lasers will benefit from the latest technologies and innovations happening in the power supply industry.
In 1917, Einstein proposed the process that makes lasers possible, called stimulated emission. He theorized that besides absorbing and emitting light spontaneously, electrons could be stimulated to emit light of a particular wavelength. It took nearly 40 years before scientists transformed Einstein's proposition to fact, putting lasers on the path to becoming the powerful and ubiquitous tools that they are today, but he also said: "I have no special talent. I am only passionately curious", and that is the motto of many power designers developing power solutions for the next generation of medical lasers.
The future of power supplies for medical lasers is bright!
rganized by Aalborg University, Denmark, the 13th International Future Energy Challenge (IFEC) 2020 announced awards for the student project competition on power supplies for nanosatellites, a fast-growing satellite industry segment. In 2020, the student teams were challenged to design and build a power supply for nanosatellites with specific requirements for efficiency, power density, weight, and dynamic performance. The competition included a preliminary proposal submitted in November 2019, two virtual technical workshops (April and August 2020), and a final competition with prototypes sent to and tested at Aalborg University in November 2020. A total of 26 project proposals were received from 13 countries and regions. Initially, 17 teams were shortlisted for the first workshop, and 10 teams were later invited for the second workshop. The final competition involved prototype testing of the four finalist teams. These tests were conducted locally at Aalborg University, where Chroma ATE Inc. sponsored the testing system. The winners are as follows:
The following teams received the Certificate of Excellence:
Initiated in 2001, the IFEC is sponsored by Power Sources Manufacturers Association (PSMA), IEEE Power Electronics Society (PELS), IEEE Power & Energy Society (PES), and IEEE Industry Application Society (IAS). In all, the IFEC 2020 was a big success, despite the challenges associated with COVID-19 and the contingency plans for the technical workshops and final competition. All participating teams and, in particular, the finalists showed excellent skills in teamwork and solving technical problems. Congratulations to all the teams on their remarkable work and innovation. We look forward to future IFECs, more importantly, to see more brilliant students disseminate and share knowledge across continents and institutions.
More information can be found on IFEC 2020 website: http://energychallenge.weebly.com/ifec-2020.html.
he PSMA Strategic Agenda for the 90s included:
As mentioned in my article in the last issue of the Update "In the Beginning", in 1990 PSMA joined IEEE IAS and PELS as a co-sponsor of APEC. I would opine that "1991 was a turning point for PSMA and APEC."
APEC 91, the first conference sponsored by the 3 organizations, was led, as continues today, by a team of volunteers representing the 3 sponsors, including General Chair Chuck Harm, PELS; Program chair Dr. Tom Jahns, IAS; and Exhibits Chair Dave Kemp, PSMA. The conference was a huge success, though not without its challenges. The Gulf War had an impact with a reduction in our projected international attendance. Our initial concerns were confirmed when David Fields of TDK-Lambda U.K. a Plenary Session speaker, cancelled. His presentation was to address the world market for power supplies. I was asked to take his slot and presented "Global Power Supply Implication...the squeeze is on." I also led an evening rap session titled "Are Power Supply Manufacturers a Band of Liars and Thieves?" During his Keynote Speech, W. J. Warwick, President of AT&T Microelectronics, mentioned the topic of my rap session, saying "he will need to know if it's safe to go back to the office."
Some notable moments from APEC social events in the 1990s:
One challenge I undertook as APEC Publicity Chair, that did not have much success, was to invite a local VIP to greet us. While most declined due to restrictions and other obligations, many did send nice letters welcoming APEC. Some of these VIPs include Presidents George H. W. Bush and Jimmy Carter; and Governors Mike Foster, Louisiana; George W., Texas; and Arnold Schwarzenegger, California.
On the other hand, I was successful in getting APEC print and broadcast media attention with a few (Micro-) mice running around a maze. The APEC '93 Micro Mouse contest was broadcast on ABC in San Diego. The San Jose Mercury News had a full color photo of the contest in their Mar 6,1996 edition. And both the Orange County Register and FOX local channel 11 covered our 2004 event in the Disneyland Hotel ballroom.
APEC 2016 in Long Beach was the last APEC I attended. It was overwhelming to see how much APEC has grown - the program committee had to sort thru 1212 Technical Session Abstracts submitted from 45 different nations. There were an amazing 370 booths in the exhibit hall! I learned a new topic called "Internet of Things." And I can reflect back to 1995 in Dallas where we offered 140 technical papers in 21 sessions with four parallel tracts.
Wishing PSMA much success as you move forward into the future.
TDK Corporation (TSE:6762) presents the fully revised version 4.0 of the tried and tested Online AlCap Useful Life Calculation Tool for EPCOS aluminum electrolytic capacitors. The tool covers all new high-voltage capacitors (>150 V DC) with screw, snap-in and solder pin connections. These DC link capacitors are particularly suitable for new designs of converters for industrial applications, such as photovoltaics and wind power generation, as well as uninterruptible power supplies.
The AlCap tool enables up to 15 load profiles to be simultaneously entered, calculated and, if so desired, stored for later use. This powerful function allows applications to be developed both with single capacitors and capacitor banks. Furthermore, the tool can perform on a customer-specific basis calculation. This merely requires the CSC code specified in the respective data sheet to be entered.
Once all relevant values have been entered, in addition to the useful life of the capacitors under defined load conditions, the user also obtains data regarding the hot-spot temperature, power dissipation and much more. Coupled with its useful lifecycle under defined load conditions, the AlCap tool provides industrial designers a solution that meets the needs of their demanding applications.
For more information visit http://www.tdk-electronics.tdk.com/
TDK Corporation presents a new, user-friendly tool to help users select the right PTC inrush current limiters (ICL) for a range of different power supply and converter topologies. The intuitive tool is available online and does not need to be downloaded. The selection process is divided into four stages: After specifying the circuit structure and the capacitor bank's total capacitance, the developer must then enter the charging voltage and the maximum ambient temperature of the PTC inrush current limiter. After this has been done, the tool displays a list of suitable components for the user, and if a parallel connection is required, the number of components required is also shown. The most important key figures are also shown, as well as links to service distributors that sell the PTC ICLs.
ctober 29, 2020, after seven months of silence due to a major upgrade of the 70 meter wide radio antenna located in Camberra, NASA sent a set of commands to the 43 year-old spacecraft, Voyager 2 that has travelled billions of miles from earth since its launch in 1977. Voyager 2 acknowledged it had received the call and executed the commands without any issue. Interesting for sure - but what is the significance of this to power engineers?
Although often considered as the last cog in the wheel by system designers, in truth the power supply is probably one of the most important parts of their equipment. From the thyratron tubes used in the type REC-30 power rectifier to supply HV power to teletype teleprinters in 1930 , through to the latest Wide Band Gap semiconductors, without their curiosity and passion, power designers would not have made a lot of things possible. Voyager 2 is a good example of that, but who remembers what happened in the late seventies and early eighties within the power industry and how leading power engineers changed the face of our industry?
Back in time to the battlefield!
Launched on August 20, 1977, Voyager 2 was powered by a Radioisotope Thermoelectric Generator (RTG) that turns heat from the decay of a radioactive material into electricity. The generated voltage is regulated and distributed to the 14 scientific instruments and to the master control board. The overall power system has been designed to accommodate the RTG and despite the schematic being kept secret, a brand new technology was mentioned, the 'switching power supply'!
Known since 1930, switching power supply principles have been explored by power designers for decades with the aerospace industry with NASA being the driving force in research and development. Considering the astronomical cost of a launch, and also the lifetime of space probes and satellites, space power designers sought for lower weight, higher energy efficiency and compactness. In the sixties NASA had already used switching power systems in a number of satellites e.g. Telstar in 1962.
In parallel with secret research conducted by aerospace and military organizations to miniaturize embedded power systems, power designers in the civil industry also considered alternative solutions to the old, heavy, bulky conventional architecture of transformer, rectifier, and linear regulation. Who launched the first commercial switching power supply is up for debate, but we can mention RO Associates who in 1967 introduced a 20Khz power solution, followed by a wave of products e.g. 1970 NEMIC Japan, 1973 HP 500W.
For leading power designers it was obvious that switching power technology was the future. But at that time linear power supplies were the standard and 'switching' was considered to be a suspicious technology. Some were predicting that the interference field generated by switching could cause major damage to the final application.
We should remember that in the seventies linear power supplies were the norm, and despite Lambda introducing a line of 'standardized' linear power supplies, the launch of Power-One's 'H' series is considered by many as the first 'off the shelf' power solution, first in USA and then in Europe. Based on a genius level concept of a folded aluminum plate used as case and power dissipater, Power-One launched an amazing number of variants offering systems designers a ready to use power supply (Figure 01).
Simultaneously in Japan - with very little information coming out from that country – power supplies manufacturers not only launched a complete range of linear power supplies but only few years after, a range of switching power solution. One example is the company ELCO/COSEL, which launched the linear "G" series in 1975, followed in 1977 by a complete range of switching power supplies, the "H" series (Figure 02)! In truth, Japan was really ahead of the curve. Another example being SONY who in 1960 at the time when the TV industry used electronics tubes (valves), were the first to use transistors in their TVs and were probably the first to implement a switching power supply in TV equipment in the early seventies.
We should also remember that in the late seventies and early eighties, the vast majority of companies developing electronics equipment had their own in-house power departments designing dedicated power solutions for their applications. Not surprisingly, for many in-house power designers the launch of the Power-One 'H' series was perceived as a threat. Many equipment manufacturers adopted standardized 'off the shelf' power supplies, refocusing their internal power department's R&D to the emerging switching power technology in order to stay ahead of their competitors.
With passion, talent and curiosity!
The seventies was full of talented engineers researching enhanced switching power solutions and it would require a dedicated article to name them all. Among all of them, I will mention here two 'power gurus', Robert J. Boschert (Boschert Associates) and Frederick Rod Holt (Apple), both working at the same time on more efficient power solutions. In both cases, as it was in the aerospace industry, they aimed to make the power supplies smaller, lighter and more efficient.
According to legend, in his kitchen in 1970, Robert Boschert started to develop a more cost effective, competitive and lighter power supply as an alternative to the bulky transformer and linear regulation model. He focused on developing a switching power supply for wheel and band printers that he produced in volume in 1974. In 1976 he launched one of the first 'off the shelf' switching power supplies and applied for patents 4,037,271 and 4,061,931 to protect its IPR (Figure 03). The two patents were granted in less than a year, followed by the commercial success of the OL25 switcher that received high profile coverage in the press and media e.g. "Flyback converters: solid-state solution to low-cost switching power supplies" published 21 December, 1978 in Electronics. Robert Boschert was also a pioneer in selling licenses of its IPR and in 1977 Boschert Inc. had more than 600 employees and was certified to design switching power solutions for space and military aircrafts.
At the same time Steve Jobs, known for his curiosity in new technology, considered switching power technology as being of interest, but due to lack of time the Apple I, launched in April 1976, featured a conventional linear power supply. But then, working on the Apple II Rob Holt designed a 38W multi-output off-line flyback switching power supply (Figure 04) for which he filled a patent in February 1978 and got it granted in December (4,130,862). Apple II was a success and with volume levels increasing, Apple outsourced the manufacturing of the power supply to ASTEC, beginning the long history of OEM power supplies for computers.
Perhaps anecdotal but nonetheless illustrating the competitive landscape within the power industry which suffered a number of IPR disputes, in Walter Isaacson's Steve Jobs biography it is written that Jobs said: "Instead of a conventional linear power supply, Holt built one like those used in oscilloscopes. It switched the power on and off not sixty times per second, but thousands of times; this allowed it to store the power for far less time, and thus throw off less heat. That switching power supply was as revolutionary as the Apple II logic board was." Jobs later added: "Rod doesn't get a lot of credit for this in the history books, but he should. Every computer now uses switching power supplies, and they all rip off Rod Holt's design."
For sure, as a good marketer Steve Jobs would like APPLE to enjoy the accolade of implementing switching power supplies in PCs, though many others e.g. IBM and HP followed the same path at the same time, all aiming for higher performance and reduced costs. However, despite the huge benefits of that technology, its implementation and market adoption has been relatively slow and market analysts have estimated that only 8% of the power supplies manufactured in 1978 were based on switching topology.
Make my Teletype smaller, lighter and faster!
In the introduction, I mentioned the thyratron power rectifier type REC-30 powering a 1930 Teletype teleprinter . Few know that, in those days, Teletypes used to be state of the art telecommunication machines, motivating power designers to invent and innovate long before the introduction of 1, 2, 3, 4 and 5G.
Besides topologies, one major evolution in the switching power supply industry occurred in 1976 when Robert Mammano, cofounder of Silicon General Semiconductors introduced the first control IC dedicated to switching power supply. The launch of the SG1524 was a major step forward within the power supply community, and its first application was a new generation of Teletype machines marketed as being 'smaller, lighter and faster'.
Originally developed to solve a Teletype manufacturing problem, the introduction of the SG1524 became the kick-off of modern switching power supplies, opening the way to inventions and innovations that we all benefit from today.
The race for switching power is open!
With the development of the personal computer and IT equipment, the demand for high efficiency and low weight increased the demand on power designers to improve performance further. Despite Steve Jobs' perception, computer leaders such as IBM had impressive power departments and the launch of the IBM 5150 Personal Computer set the tempo for the design of a dedicated power supply using the NE5560 and later the SG3524 chip. Unique to the PC industry, switching power supplies are specific to a motherboard and are not as such 'off the shelf' for common applications use, although the snowball effect on contracted manufacturers contributed to boost their own products' development, launching complete ranges of commercial products.
On the industrial side it is impossible to name all the products and innovations but since we mentioned the Power-One 'H' series, it is fitting to mention a young engineer who joined Power-One in the early eighties, Steve Goldman, who led the team that designed the new generation of switching power supplies, the MAP series. Anecdotally, MAP stands for the name of Power-One's Chief Engineer/Designer at that time, Michael Archer (Michael Archer Product).
Simultaneously the computing and industrial industries moved towards switching power architectures and although it took years before that technology prevailed over the well-established linear solution, a number of power electronics conventions started all around the world, providing a forum for power engineers to learn and share knowledge about new technologies.
1980, the pivotal point in the power industry!
At the end of the seventies and the beginning of the eighties the power industry forged the foundations of where we are today. While the IEEE Power Electronics Specialist Conference (PESC) started in 1970, power designers and industry leaders sought a different type of forum to share technology knowledge, new ideas and best practices. POWERCON took place in Beverly Hills, CA, March 20 to 22, 1975, followed in 1978 by a conference primarily focused on telecommunications called INTELEC. Unfortunately, after nine years POWERCON ceased in 1984 leaving the power community as an orphan.
Back in days when the grandfather of the internet, ARPANET had just adopted the TCP/IP protocol (January 1983), power engineers were still miles away from chatting and blogging, and with the growing demand for tighter cooperation within the power industry the need for a 'one place to share' became obvious. In 1983 the China Power Supply Society (CPSS) was founded, and in 1985 the Power Sources Manufacturers Association (PSMA) was incorporated. Both organizations aimed to share knowledge and to facilitate communication within their respective power communities, and 35 years later both are still supporting power engineers.
At the same time that PSMA was formed, a group of eight passionate engineers, Bill Hazen (Prime Computer) ; Don Drinkwater (DEC) ; Phil Hower (Unitrode) ; Jonathan Wood (Data General) ; Marty Schlecht (MIT) ; Jack Wright (GE) ; Trey Burns (Data General) and John Kassakian (MIT) had an idea to create a power conference which would embrace research, applied electronics, and serve to connect electronics engineers to a larger community including industry, and the provision of an exhibition. It was to be called the Applied Power Electronics Conference and Exposition (APEC), and the first edition took place on 28 April to 1 May, 1986 in New Orleans.
And the story continues…
The power electronics industry has been through many periods of evolution, disruption and revolution. If the introduction of the Bipolar Junction Transistor was arguably the 'first' technological revolution, there is no doubt that the migration from linear power conversion to switching technology was the second, and the beginning of a long evolutionary path.
Forty-three years after it was the launched, Voyager 2 has travelled 14 billion miles into deep space and the power supplies that pioneers designed in the early seventies are still doing their jobs. This is what makes all of us excited by what we do in the power industry and thanks go to all the genius power designers that I have been unable to name in this article that have contributed to make the transition from linear to switching technology possible.
WOW!. Happy 35th Anniversary PSMA.
In the 1970s and early 80s the power electronics industry encountered a huge leap in power supply design technology driven in part by the introduction by Apple and IBM of personal computers. Up until that time, the technology primarily used was large and heavy linear technology power conversion, "boat anchors" manufactured in two car garages as the expression went. During that time, the industry also began to face the challenge of transitioning to bi-polar and high frequency MOSFET designs that would create more efficient, smaller, and lighter products. This encouraged a group of design engineers and marketing leaders to explore creating a new industry group to focus on educating themselves and their customers as the industry began to implement and accept these evolving power technologies. At that time Electro, PowerCon and Westcon were the trade shows and conventions focusing on power electronics.
On Nov 15, 1985, the Power Sources Manufacturers Association, PSMA, was founded as a 501 C (6) nonprofit industry association. Three months later, in Feb of 1986, the first Board of Directors were elected at a meeting held in Dallas, TX. Tim Parrott served as President and Ron Koslow was PSMA's first Chairman. The Bylaws identified three levels of membership – Regular (Manufacturers of power sources and conversion equipment), Associate (Users of power sources and conversion equipment, or manufacturers of components designed for incorporation into power sources and conversion equipment) and Affiliate (Organizations involved in the power industry, including Manufacturer's Representatives, Distributors, Advertising, Marketing, Consulting, Publications).
PSMA launches third year
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To establish early credibility, the Board decided to create a "Handbook of Standardized Terminology for the Power Sources Industry". Michael Foldes led the Technical Committee that also included Dan Ketchum, Earl Crandall, Emilie Creagar, Chris DuBiel, Gene Goldberg, Sydele Petch and myself. This was before email and online collaboration tools; Michael sent us each an 8" disc for making our corrections suggestions and additions
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To provide industry exposure PSMA co-sponsored the Power Electronics Conference, PEC, in San Jose in Feb of 1989. PSMA Chairman Art Hamill said, "we believe there is a need for an industry-wide forum which brings together the component suppliers, manufacturers and users of power sources and suppliers. That conference and exposition offered six half day Professional Education Seminars and nine Technical Sessions. One year later, in February 1990, PEC was held at the Long Beach California Convention Center and featured three tracks of "Issue Forums" to discuss industry trends.
To create "deliverables" a Research and Development Committee was formed, led by Donald Staffiere of Digital Equipment and John Woodard of ITT Power Systems, with members representing suppliers, users and university members. In 1990, the committee completed its first report to the Association on the status of R&D in the world and presented the results at the PSMA Annual Convention held in Long Beach, CA in conjunction with PEC. This report evolved over time into the current PSMA Power Technology Roadmap.
In March of 1990, John Steel represented PSMA at an IEEE PELS Power Electronics Retreat with leaders from industry and academia. Interestingly, the meeting minutes contained a sidebar that read, "This was the high energy point of the day. Even though we didn't quite know what that meant, we liked the words 'GREEN ENERGY".
Larry Gilbert, John Rowbottom and Dave Kemp at the PSMA booth at the 1990 Canadian High Technology Show
( Click to enlarge )
Expanding PSMA's exposure, later that year we participated at the Canadian High Technology Show in Toronto. We conducted a Customer-Supplier partnership forum, Norm Berkowitz of Computer Products and myself representing the US, and Glen Belland (Electronic Craftsman) and John Rowbottom (NCR) representing Canada.
After the 1990 PEC and APEC conferences, a group representing PSMA negotiated with representatives of PELS and IAS to become the third financial and technical sponsor of APEC (Applied Power Electronics Conference). The Sponsor Agreement on the Continuing Operation of APEC was written by Bob White and the signers were John M. Steel, PSMA Chairman, Ronald M. Jackson, President IEEE Industrial Applications Society (IAS), and Thomas G. Wilson, President IEEE Power Electronics Society (PELS). In Jan of 1991, Dave Kemp and I were appointed Co-chairs of the APEC Technical Program Committee.
There are so many more names that deserve a shout out in the first five years of PSMA. A partial list of the PSMA family at that time includes: Norm Berkowitz, Mike Brown, Lee Campbell, Frank Cathell, Earl Crandall, Emilie Creagar, Chris DuBiel, Mike Foldes, Paul Fulton, Gene Goldberg, Art Hamill, Albert Himy, Dave Kemp, Dan Ketchum, Jim Kimball, Ron Koslow, John Lombardi, Sr., Doug McIlvoy, Mohan Mankikar, Chuck Mullett, Tim Parrott, Sydele Petch, Stu Roberts, Jeff Shepard, Don Staffiere, John Steel, David Thompson, Dean Venable, Ole Vigerstol, Bob White and John Woodard.
We hope to include another article on the early history of PSMA in a future issue of the UPDATE
Provided by Larry Gilbert,
The UL/EN/IEC 62368 standard is a merger of two standards—UL/EN/IEC 60065 Audio and Video Equipment and UL/EN/IEC 60950 Information and Communication Equipment. As with other standards, there are different versions or editions of the standard such as IEC 62368-1 2014. As this standard applies to a broad range of popular applications, many designers are affected by its requirements.
Most designers probably have some familiarity with 62368 because the industry has been transitioning to this standard for several years, and, within the U.S., this standard replaced the legacy standards in June 2019 for any new products seeking certification. However, there's another regulatory milestone looming as the legacy standards in the European Union are about to be withdrawn on December 20, 2020, making this essentially the adoption date for 62368 in the EU. (1)
As this deadline approaches, many designers may still need to come up to speed on what the standard requires, and understand what variations of the standard are being applied as well as aspects of the standard that are still in flux. With that in mind, we present a brief overview and update on UL/EN/IEC 62368, noting the status of various versions of the standard in different countries and sources for further information. We also highlight a few elements of IEC 62368 such as standards-related terminology, touch temperature limits and two application areas that will be impacted by anticipated changes in IEC 62368, namely indoor and outdoor equipment and products with USB and PoE interfaces.
Under the emerging regulatory changes, the label on each of the appliance products changes and there are new requirements for each product. For example, the labeling required in the old (EC) no 642/2009 and (EU) 1062/2010, which apply to TVs and monitors, changes in the new regulation. While the existing product ratings assign A, A+, A++, and A+++, the new rating system goes from A through G (more on this in the section on Displays).
Safety and Hazard Based
IEC 62368 is not a rule-based standard but rather a safety and hazard-based standard. Audio and video equipment and information communications equipment have many ports such as USB and the newer USB Type C ports. The computer monitor has ports that the consumer or user can touch. The manufacturers are now requested to present hazards to the safety agencies including voltage, and temperatures of the various surfaces.
Table 1. IEC 62368 implementation by country or
It has taken time for the various agencies to create a harmonized standard. Each region of the world has its own version and implementation date as seen in Table 1.
UL has given a number of presentations and overviews concerning the standard. One of the earlier presentations was an IEC 62368-1 overview given by Thomas Burke a principal product safety engineer, Consumer and Enterprise Tech Equipment at UL, on June 7, 2017 to PSMA. A recording of the presentation along with the slides is available on the Safety and Compliance Forum on the PSMA website.
More recently Dennis Butcher, senior project engineer, Ctech EULA, gave a webinar presentation on July 28, 2020 "The Adoption of IEC 62368-1 3rd Edition and IEC 62368-3." This presentation is available from UL's Toolkit page. This web page offers resources to help engineers and compliance engineers navigate the IEC 62368-1 3rd Edition from UL 60065 and the UL 60950 standards.
There are a number of editions to IEC 62368-1 including 62368-1 2nd Edition 2014, which is often cited in the literature. There's also UL/CSA 62368-1 3rd Edition. which was published Oct. 4, 2018. This paper cannot address many of the differences found in the variations because these variations apply to different products and each product is different and has different uses.
Testing and Design Assistance
Many companies have a compliance engineering department. This department gathers the standards for the products for safety and regulations for various parts of the world where the company's products are sold. The compliance department needs to have a good understanding of the language used in the standards because in many cases, this language may not be understood by design engineers. The following was taken from the Thomas Burke presentation defining some differences.
Table 2. Definitions used by IEC 60950-1 verse IEC
In products where consumers can touch various parts of the product, there are issues with both temperature and electric shock. Table 3 lists temperature limits under the standard for accessible (touchable) parts.
Table 3. Touch temperature limits imposed by IEC
Indoor Outdoor Equipment
Because the 62368 standard did not address all industry concerns, there are cases where it has not supplanted the old standard. This is true for outdoor applications. As the following excerpt  explains, the second edition of 62368 still references IEC 60950-22 with regard to outdoor equipment. However, the third edition of the standard will include the 60950-22 requirements in an Annex Y as noted. Some of these requirements are still not fully defined. So, some unsettled issues remain and other agencies will need to help address what is to be applied.
USB And PoE
Another case where the legacy 60950 requirements have remained in effect are the interfaces that transmit both data and power. For example, many pieces of equipment use USB for both data and power. This is true for the newer USB Type C cables that can eliminate product power supplies and the associated ac power cords.
Similarly, many security cameras and monitors use CAT 5 and CAT 6 cables for both power and data information following the power over Ethernet (PoE) standards. Both of these interfaces will be covered in the third edition of IEC 62368-1 as shown in the following excerpt. 
There are newer lighting products that are using CAT 5 and CAT 6 cable systems for both hallway lighting in hotels and security cameras. Some of these systems have backup dc power in case of a power outage. These systems use the new LED lights, allowing lower power consumption and long periods of operation such as two or three hours, which was unheard of with emergency exit lighting and security cameras in the past.
These lighting products came onto the market after the 62368 was initially published so they weren't covered. And there are others such as video doorbells, which can use the existing power and can even have a battery backup using Li-ion batteries. But it's expected that these products will be covered in the third or fourth editions.
- "Getting to Know IEC 62368-1—How Does A TV/Stereo Standard Affect My Industrial Power Electronics Design?" by Kevin Parmenter and James Spangler, How2Power Today, November 2017
- "IEC 62368-1 Overview" by Tom Burke, UL Presentation to PSMA Safety & Compliance Committee, 6/7/2017.
- "The Adoption of IEC 62368-1 3rd Edition and IEC 62368-3"webinar by Dennis Butcher, July 2020, available at "UL's ToolKit for Your 62368-1 Transition".
Director of Applications Engineering
Taiwan Semiconductor America
Spangler Prototype Inc. (SPI)
Editor's Note: This article was first published in the September 2020 issue of How2Power Today (http://www.how2power.com/newsletters/index.php).
ver the past five years, the PSMA Magnetics Committee has sponsored five Special Projects to better understand the flux propagation in ferrites and the reasons why the performance of large inductor cores performed so poorly compared to the expectations based on published specifications from the suppliers.
The first three projects - PSMA -Dartmouth Core Loss studies- were undertaken by Dartmouth under the leadership of Professor Charles Sullivan and the results are available on the Magnetics Forum on the PSMA web site. Based on some of the insights from these projects formed the basis for the 2 most recent projects – PSMA- SMA Core Loss Studies Phase 1 and Phase 2.
The last two Core Loss Studies are now complete, and this article highlights some of the most interesting findings. This article is not as comprehensive as the reports, and the reader is encouraged to read the full reports on the PSMA web site for more information.
PSMA–SMA Core Loss Study Collaboration
SMA Magnetics was interested in why large inductor cores performed so poorly compared to expectations based upon published specifications. At the the same time, PSMA was interested in flux propagation in ferrites and why the performance factor B*f was lower and peaked at a lower frequency for larger cores.
Charlie Sullivan (Dartmouth) recognized that there was significant overlap in these interests and arranged an introduction which resulted in the Phase I PSMA-SMA core Loss study. The findings of the Phase I study were so intriguing that a Phase II study followed, which built upon the data from Phase I.
The Phase I and Phase II test reports can be found on the PSMA website Core Loss Studies tab of the Magnetics Forum. The Phase I report is publicly available; Phase II is currently only available to PSMA members, and will be publicly available in late 2021.
PSMA - SMA special project – Phase I
The purpose of the Phase I PSMA-SMA Core Loss projects was to study the flux distribution within ferrite cores while operating. The concept is that a small area internal to the core can be enclosed by a test winding inserted into drilled holes. The voltage on the test windings shows the dφ/dt of the flux.
Initially, eight specially machined cores, two each of four materials, were made by Fair-Rite. Three holes were drilled into each core so that flux in the innermost 1/9th of the core area could be compared to the excitation. These cores were shipped to SMA for study.
Although the original scope was to test these eight cores, SMA drilled seven more 50 mm cores of various materials to provide a larger sample.
A surprising result for some of the cores was that the flux density in the center of the core was much higher than the average flux density, peaking at just over 2.5 times. Further, it had a large leading phase.
PSMA - SMA special project – Phase II
Phase II was a larger study comprising five parts:
1. Large core testing–flux propagation in ferrites
Several large cores were drilled with nine holes so that three sets of wires enclosed progressively smaller internal areas. In this way, the flux and flux density can be measured in three shells and the center for comparison with the excitation voltage.
Two other large cores were drilled so that the voltage can be measured around any of 49 segments. Each segment is the same size, 1/49 of the total, so one-to-one comparisons could be made.
2. Core power loss comparison with different sized cores of the same material.
Large cores of the same material were found to have significantly higher losses when compared on the basis of mw/cm3. This suggests that core loss for different core sizes cannot be calculated based on material specifications, which are usually taken using a "standard" core of about 2.5 cm outside diameter.
3. Core shape effect on power loss
Core losses were significantly lower for a core that was laminated. The second core above has the same area, volume and weight as the first core, but it comprises 5 thinner laminations.
Core losses were significantly lower for a core that was hollowed out. The second core has the same ID, OD and height as the first core. Its area, volume and weight are lower, so higher losses may be expected at very low frequencies.
The four cores above all are the same weight and volume. Cores 1, 2 and 3 have the same ID but cores 2 and 3 are stacked and have the same area, volume and weight as core 1. Core 4 has five times the area because it is wound with only one turn, but it has the same volume and weight as the others.
The inductances of the four cores are very close to the same value, as are their other electrical properties except the core loss. The multi-core stacks have significantly lower core loss.
4. Ferrites electrical properties
The electrical parameters (permittivity, permeability, and conductivity) of various ferrites were measured. These must be known accurately to model the core performance successfully.
As an example, Finite Element Analysis (FAE) did not model the observed flux distribution very well using traditional parameters from data sheets. Once the analysis was modified to use accurate parameters, the analysis was greatly improved.
5. Rectangular wave core loss tester
Part of the Phase II core loss program was developing an improved full-bridge rectangular wave driver for core loss testing. The wave shape is determined by an arbitrary waveform generator under software control. The voltage is controlled by a programmable power supply. The time, voltage and current are measured using a high accuracy digital sampling oscilloscope and the parameters are exported to a spreadsheet for post processing and storage. All of the software operations are written in Python.
PSMA Magnetics Committee
In addition to sponsoring these five core loss studies, the PSMA Magnetics Committee continues to be very active. They have organized 5 "Power Magnetics @ High Frequency" workshops in addition to conducting very successful APEC Industry Sessions each year. They also presented two educational webinars as part of the "PSMA Basics of Magnetics for Switching Power Webinar Series" in early 2020. The committee meets about once a month by webconference and anyone interested is invited to participate. Contact the PSMA office at firstname.lastname@example.org for more information.
Provided by Ed Herbert, PSMA Magnetics Committee Co-Chair
The International Electronics Manufacturing Initiative (iNEMI) today announced publication of “Recommended Best Practices for Protecting the Reliability and Integrity of Electronic Products and Assemblies when Disinfecting for SARSCoV- 2 (COVID-19).”
Developed by a team of experts from across the member organizations of the International Electronics Manufacturing Initiative (iNEMI), this document provides guidance on how to mitigate the possible detrimental impact of disinfecting procedures on electronic equipment and assemblies. Groups such as the U.S. EPA, CDC and the World Health Organization (WHO) have published general guidelines regarding cleaning and disinfecting for COVID-19, but none of these specifically address the impact of disinfectants and their application methods on electronic equipment and assemblies. Many commonly recommended disinfection substances and/or application methods could potentially cause failures in electronic equipment.
To develop these best practices, the iNEMI team reviewed key industry, government and technical sources. They also assessed the chemicals included in the U.S. EPA List N: Disinfectants for Use Against SARS-CoV-2 (COVID-19) and common application methods, identifying those substances that minimize the risk of negative impact on electronic equipment when applied in an appropriate manner.
“With the COVID-19 crisis, several of our members have contacted iNEMI for guidance on how to mitigate the possible detrimental impact of disinfecting procedures on electronic equipment and assemblies,” said Marc Benowitz, iNEMI CEO. “There are guidelines from groups such as the U.S. EPA, CDC and the World Health Organization (WHO) regarding cleaning and disinfecting for COVID-19, but none of these address the impact of disinfectants and their application methods on electronic equipment and assemblies.”
“Many commonly recommended disinfection substances and/or application methods could potentially cause failures in electronic equipment if the internal electronics were inadvertently exposed to them,” continued Benowitz. “This is an obvious concern for electronics manufacturers who are wanting to ensure the safety of their employees, supply chain partners and customers, while protecting the reliability and integrity of their products.”
Benowitz explains that, in response to this industry need, a team of experts from across iNEMI member organizations reviewed key industry, government and technical sources and assembled a best practices document. The team assessed the chemicals included in the U.S. EPA List N: Disinfectants for Use Against SARS-CoV-2 (COVID-19) and common application methods, identifying those substances that minimize the risk of negative impact on electronic equipment when applied in an appropriate manner.
iNEMI’s best practices are now available to download here.
he Power Sources Manufacturers Association (PSMA) announced the opening of the popular Safety & Compliance Standards Database (SCDB) and Energy Efficiency Regulations Database (EEDB) to the industry with no registration required. You can find information about a Regulation or Standard, its most recent version, revision history, or the latest agency updating work. PSMA has successfully offered the EEDB and SCDB databases to the industry at no charge to the user for several years. Now access is even easier with neither a registration nor log-in required to access all of this industry regulations and standards information.
Every product sold today must meet the requirements of agency regulations, and ultimately standards. Each country or group of countries may have different requirements. It is critical to know the specific ones which your product must comply and the ones requiring compliance within the next two to four years, products you are probably just commencing to design. Since there are numerous regulations and standards, the SCDB and EEDB databases simplify access to the one you need to find. The specifics for each of these databases and how you can easily find them is as follows.
To find the databases, go the PSMA Home Page www.psma.com and follow the links to the database or use the direct links:
- EEDB www.psma.com/technical-forums/energy-management/database
- SCDB www.psma.com/technical-forums/safety/database
The Energy Efficiency Database (EEDB)
PSMA Energy Management Committee sponsors the Energy Efficiency Database, which covers energy efficiency regulations globally for power supplies and motor drives. This database presently tracks on a daily basis 56 agencies and 521 regulations. A significant number of regulations are presently under revision, or revision is complete to become active in 2021/2022.
Figure 1 shows the regulation selection page. You can select a specific agency by application, country or state, or global region. You can also select a regulation by the application. The "Recent or Upcoming Events" section lists all the latest work on all regulations tracked by the database with the most recent date first.
Figure 1 – Energy Efficiency Database
The Safety & Compliance Database (SCDB)
The PSMA Safety & Compliance Committee sponsors the SCDB, which monitors the Power Electronics Standards globally. Presently, this database tracks 778 standards from 50 agencies. The Standards categories include: Product Safety, EMC, Material Toxicity, Environmental, Quality Standard, Performance, Energy Efficiency, and Fundamental Standard.
Figure 2 shows the standard selection page. As with EEDB, you may select a specific agency by application, country or state, or global region. If you have the standard number, you can find it quickly in the bottom selection menu box. The "Recent or Upcoming Events" section lists all the latest work on all standards tracked by the database by the latest date first.
Figure 2 - Safety & Compliance Database Standards Selection Page with Agency Drop List
And… PSMA Helps You to Stay Up-to-Date Weekly
PSMA further simplifies your access to Regulation updates and Standard updates by offering weekly email announcements containing the latest "Recent or Upcoming Events". This permits you to stay current automatically with present change considerations and work in process on standards and regulations upgrades. There are an average of 30 updates each month from agencies around the globe which the PSMA database team gathers and includes in the weekly email updates. To receive this service, which is provided at no cost to the recipient, you just need to sign up, provide your email address and select the update announcements you want to receive - SCDB, EEDB or both.
The direct links to sign up for email updates to the EEDB data base is https://www.psma.com/webforms/psma-energy-efficiency-database-email-sign.
The direct link to sign up for email updates to the SCDB is https://www.psma.com/webforms/psma-safety-compliance-database-email-sign.
an you believe that the PSMA & APEC are both 35 years young this year? We can look back on our accomplishments and look forward to what we will achieve in the next decade. That means that there is still time to add to the list of accomplishments. For inspiration, here are some PSMA accomplishments over the years:
If your company is not yet a member of PSMA, visit www.psma.com/membership/benefits to learn more about joining PSMA and adding your voice to the almost 200 companies, organizations and educators who for 35 years have worked together to support the mission and initiatives of PSMA and to influence the directions of the Power Sources Industry.
Consider how you can contribute to the many opportunities this year, here are few to get started:
If you are interested in any of these opportunities, email email@example.com.
In addition, all of the PSMA Technical Committees welcome your participation in planning and organizing industry sessions for APEC 2021. Help to raise the bar for APEC 2021 Industry Sessions with new presenters with different views discussing their perspectives. Regardless of whether APEC 2021 is the traditional in person conference or virtual event, people still need to hear new points of view and interact with others to discuss the emerging opportunities in the power electronics industry.
APEC has grown and evolved from the first conference in 1986 with 250 Attendees and 20 Exhibitors while staying true to the original ideals, solidifying its status as the leading conference for practicing power electronics professionals. View the APEC 35th Anniversary presentation to see the conference roots and learn more about the volunteers starting with the original "Gang of 8" who have made APEC so successful!
Provided by Ada Cheng and Frank Cirolia
The Power Sources Manufacturers Association announces a series of webinars as a lead-up to the next edition of the PSMA Power Technology Roadmap (PTR). The webinar series, organized by the PSMA Power Technology Roadmap Committee, will feature invited experts from different fields to offer a range of technological perspectives. In addition to setting the groundwork and providing input for the next PTR, the webinars will give participants access to expert opinions on technology trends and include a question and answer session at the end of each session.
The webinar series will include a number of highly regarded industry and academic experts covering a variety of topics covering components, systems, packaging and applications. The series began on February 20 with a presentation by Ajay Hari of ON Semiconductor "Utilizing WBG Devices in Next Generation Power Converters." Two webinars were held in May, "JEDEC JC-70 Issues Industry First Guidelines for Testing and Evaluating Wide Bandgap Power Devices" presented by Stephanie Watts Butler, Texas Instruments and Peter Friedrichs, Infineon; and "Powering & Retrofitting IoT Devices for Industry 4.0" by Mike Hayes and Peter Haigh, Tyndall National Institute. Future topics include "Ultra-High Density Double-Sided Half-Bridge Packaging with Organic Laminates", "Advanced Packaging Concepts for Wide Band Gap Power Electronics", "Switching Performance of Wide Band Gap Devices", and many others.
Webinars are tentatively scheduled to be held every other Thursday from 10:00-11:00 a.m. Central Time. For updates to the schedule and news of webinars that will be added, please visit: www.psma.com/technical-forums/roadmap/news-events and follow us on LinkedIn and Twitter. To join the PSMA mailing list to receive invitations to all upcoming webinars, sign up at www.psma.com/webforms/psma-email
The Power Technology Roadmap provides a consolidated outlook of trends in power conversion technology for the next two to five years. The trends provided in the report are intended to give a broad outlook of the power conversion technologies, components and applications. The complete Roadmap document has been published every two or three years, incorporating the content of the Roadmap Webinars Series conducted over the months prior to publication. The other content for the PTR is sourced from recognized industry experts and comprises write-ups about trends in components, applications, emerging technologies and university research. It also includes a comprehensive projection of key metrics evolution in four selected power conversion technologies (ac-dc front-end power supplies, ac-dc external power supplies, isolated dc-dc converters and non-isolated dc-dc converters).
Conor Quinn of Artesyn Embedded Technologies and Dhaval Dalal of ACP Technologies, Power Technology Roadmap Committee Co-chairs, stated; "The PTR webinars provide a window into technology trends and the presentations are unique in terms of their diversity of perspectives, commercial-free tone and the opportunity they offer for the audience to interact with industry experts. We are always looking to enrich and expand our panel of webinar presenters and we welcome suggestions and proposals from prospective speakers." Joe Horzepa, PSMA Executive Director, added that the Committee "welcomes and invites subject matter experts who are willing to actively participate and contribute to the development of the next PSMA Power Technology Roadmap to contact the PSMA Association Office at firstname.lastname@example.org."
The PSMA Board of Directors is seeking one or more volunteers interested in providing leadership for the Safety & Compliance Technical Committee. The membership in all the PSMA Technical Committees is comprised of individual volunteers from both Member and non-Member Companies who have a technical, business or personal interest and are involved in the focus of the specific Technical Committee.
An important role of the Technical Committee leadership is to coordinate the mission and focus of the committee to address the current issues and changing trends in the technologies. Each of the Technical Committees normally meet monthly via teleconference for one hour to discuss special Projects that PSMA might fund that would benefit the membership and industry, to consider and plan Industry Sessions for upcoming APEC meetings, and to support the PSMA Power Technology Roadmap with relevant Webinars and technical content. The leadership position is the chair (or co-chair) for each meeting and is responsible for generating the monthly meeting agenda and to facilitate the meeting to meet the interests of the participants.
The benefits of Technical Committee leadership are many, including:
- Being acknowledged as an important participant and factor in the technical community
- Opportunity to interact with National, State and Independent Agencies involved with the specific technologies
- Anticipate and influence changes especially in regulations and technologies
- Identify your company as an important participant and contributor in the industry segment
- An expanded ability to network with others in the industry
Additional information on this opportunity is available here.
Please contact the Association Office (email@example.com, 973-543-9660) for more information on the specific responsibilities for the Chair and/or Co-chair of the Safety and Compliance Technical Committee.
he PSMA is a not-for-profit organization incorporated in the state of California whose purpose is to enhance the stature and reputation of its members and their products, to improve their knowledge of technological and other developments related to power sources, and to educate the entire electronics industry, plus academia, as well as government and industry agencies as to the importance of, and relevant applications for, all types of power sources and conversion devices.
By joining with other leaders in the Industry, you and your company will have a greater voice and influence on the directions of the Power Sources Industry. Some specific benefits of membership include:
PSMA membership dues are modest in comparison to the benefits offered. Is your company a member of PSMA? If not, why not? You can find the membership application on the PSMA web site at http://www.psma.com/webforms/psma-membership-application.
We look forward to receiving your application in the near future so you can take advantage of the registration discount at APEC. The 2015 Power Technology Roadmap will be available in mid March and all Regular and Associate members of PSMA will receive a free copy of the report as a benefit of membership. Affiliate members will receive a discount on the Roadmap and other PSMA reports.
The Power Sources Manufacturers Association has drafted a power electronics timeline and a "corporate" genealogy chart for the industry to review. As we get inputs, we will be updating these files on a periodic basis. Consequently these files are subject to change until we hear from all affected parties or until enough time has transpired at which time the files will be finalized.
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The Handbook of Standardized Terminology For The Power Sources Industry-Third Edition - has been made available as a download on the Members Only area of the PSMA website. Revised and expanded, this unique publication includes definitions for more than 1200 terms related to power electronics which were especially selected for the power electronics professional. The Third Edition also contains illustrations and four new appendices, including a listing of EMI specifications, excerpts from international standards of units and symbols, along with guides for authors of technical papers. Many new magnetic terms are described in this new 126-page third edition that are of particular interest to the practicing designer and marketer of power supplies and related products. Valuable information regarding worldwide power sources, standards agencies, and military specifications has been retained, updated and expanded from the previous edition. Titles of the appendices are: Testing and Standards Agencies; Designer's Reference; World Voltages and Frequencies; Military Specifications; EMI Specifications; Writing Technical Papers for Archival Publications; Units, Symbols and Style Guide; A Brief Writing Guide. These added resources provide concise, easy-to-use references for engineeers involved in technical writing and presentations. If your company is a member of PSMA, you may register for the "Members Only" area using your email address. The registration form requires you to enter your company PSMA member number. You may contact the Association Office if you do not know the member number.
Years ago we had to surround ourselves with printed reference material to provide the data on components used in our designs and applications papers to help in their use. Many of these were free, but some others cost over $100 each and became obsolete almost as fast as we obtained them. Today, the picture has changed dramatically. Most of this information is available at no cost through the Internet; the amount of information is so huge that the new challenge is sorting it out. When the semiconductor committee of PSMA began to study the problem of helping engineers find the information needed, the change in the way we do our jobs became blatantly obvious. Even this task has been made easier, because of help from the Internet.
Here is our conclusion: Google is perhaps the most advanced search engine in the world at this time. Surprisingly, it’s not just for lay people who are looking for new recipes or ways to remodel their bedrooms. Its capability to provide us with the sophisticated technical help we need is astounding. It has the capacity to improve its performance, on its own, as it is used. Our job in helping our members and others in the industry has been reduced from one of searching, rating and cataloging materials to one of simply providing a few hints about using Google. We suggest you try it for yourself, get familiar with its capability, and use it the next time you need information. Here are some examples for you to try:
1. Go to Google.com and type in power factor correction. Our result was that 2,190,000 references were retrieved in 0.23 seconds. Now, type in “power factor correction” and see the difference. We got 155,000 references in about the same amount of time. What is even more amazing is that the references were valid! Even in the first case---we looked through the first 120 on the list, and didn’t find even one irrelevant citing.
2. Try “mag amp” and retrieve 8,870 references. All were valid until we got down to the 29th one on the list, which referred to a slow-release garden fertilizer. 28 out of 29 is a validity score of 96.6%---not bad for software!!!
In Example 1 we saw the difference of enclosing the phrase in quotation marks. Doing so causes the search engine to look for precisely that phrase. Without this, the search engine will find hits on each of the words individually, inviting irrelevant references.
To the right of the search window on the home page you will find “Advanced Search.” Clicking on it will produce a page full of easy-to-use tricks to improve the search, including “Advanced Search Tips” on the top line of the page. This gives even more useful information to produce more effective results. Google is so easy that if you’ll spend only 5 minutes with it, you’ll be producing better results than you can find in a world-class library, without leaving your desk. Try it first, then try other search engines. We did this, and found a plethora of irrelevant “hits.” We invite your comments.
A discussion of criteria to consider when deciding whether you should make or buy power supplies when creating equipment.