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IN THIS ISSUE:
» Ruggedizing Buck Converters For Space And Other High Radiation Environments
» Improving Solar Inverter Reliability: Techniques For Protecting Output Power Switches
» Resonant Current Source Powers Arbitrary Load
» Developing A 25-kW SiC-Based Fast DC Charger (Part 7): Auxiliary Power Supply Units For 800-V EV Chargers
» Focus On Magnetics:
A Simplified Winding Design Procedure For Transformers
» Spotlight On Safety & Compliance:
Comprehensive Reference On Transient Protection Includes Supercaps
» New Power Products
» New on How2Power.com
» Other Top Power News
From the Editor's Desk David G. Morrison
Editor, HOW2POWER TODAY
I started the new year by attending a major industry event in the same way I participated in various conferences and trade shows last year—online. While watching presentations at home from my laptop was nothing like my past years’ experiences in walking through the massive exhibit halls of CES in Las Vegas, it still fired my imagination. The keynotes I watched discussed the technical progress the speakers’ companies are making in diverse areas such as televisions, appliances, automotive, and healthcare. Beyond the keynotes, other CES talks addressed areas such as space tech, food tech, block chain, crypto, 5G, robotics, drones, AI and many others. In the keynotes, there were instances where power topics such as batteries and energy efficiency came to the fore, such as when discussing corporate goals for sustainability or rolling out the new generations of EVs. But the bigger picture conveyed by participating in CES—even virtually—is that technology continues to make inroads into every aspect of our lives, and power electronics will be play a crucial role in this ever expanding world of applications. If you have the opportunity to attend shows like CES, especially when they offer an online edition, take advantage of the chance to see the bigger picture of how your work in power electronics could be affecting the development of new products and industries, or the opportunities you may have to do so in the future. Not quite as expansive as CES, this issue of the newsletter nevertheless addresses intriguing topics such as development of rad hard power semiconductors, the usefulness of resonant current sources, circuit protection techniques for solar inverters, aux power supply design for fast EV chargers, transformer winding design and more.
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HOW2POWER EXCLUSIVE DESIGN ARTICLES 
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Ruggedizing Buck Converters For Space And Other High Radiation Environments
by Nazzareno (Reno) Rossetti, Alphacore, Tempe, Ariz.
Any off-the-shelf component utilized in a space application will likely degrade and fail prematurely once exposed to the severity of the space environment. But not all is lost, as a wealth of ruggedization techniques are able to meet the challenges of this unforgiving environment. In this article, we review the effect of radiation on passive and active electronic components and the technologies, processes and device techniques that make them radiation-tolerant or radiation-hard. Subsequently we discuss Alphacore’s design of a radiation-hardened dc-dc converter at the heart of a space power management and distribution system. Able to properly function at up to 200 Mrad of TID, the converter can operate within the large hadron collider at CERN, and in space satellite and probe missions.
Read the article…
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Combining the improved SEE rad-hard
performance of SJ devices and TID
robust ELT devices, the cascode
structure has both improved radiation
tolerance performance and high
breakdown voltage. |
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In popular inverter controller ICs,
there’s a significant delay in the
activation of current limiting, making
power MOSFETs vulnerable to failure
under short-circuit conditions. |
Improving Solar Inverter Reliability: Techniques For Protecting Output Power Switches
by Jerry Steele, Red Hill Labs, Tucson, Ariz.
Ac power inverter reliability is a concern in a variety of fields ranging from utility to industrial power systems. However, this article focuses on another inverter application area—inverters used in off-grid and grid-tied, photovoltaic systems for residential rather than commercial use. The power range for such inverters ranges from several hundred watts to about 20 kW. Very little has been written regarding the most stressed devices in the inverter—that is, the output power switches and associated circuitry. Inverter output switch design is a key area that needs attention to achieve improvements in inverter failure rates. This article discusses the benefits of foldback current limiting and other techniques in protecting the MOSFETs.
Read the article…
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Resonant Current Source Powers Arbitrary Load
by Gregory Mirsky, Design Engineer, Deer Park, Ill.
There is a little-known class of ac current sources whose operation is based on the effect of limiting ac load current in a series resonant circuit if the load is connected in parallel to the resonant capacitor. Since this circuit can be used as a good ac current source, it is safe at the load short circuit and can be used as a step-up converter for supplying loads at voltages which are not physically practical using conventional converter circuits. Step-up coefficients in the resonant circuits can attain values of 15 to 20 and higher at efficiency above 95%. Moreover, the circuit property of pushing constant ac current to the load does not depend on the load type: it works equally well into a reactive or a resistive load and even into a rectifier. This ability to supply unchangeable ac current into any type of load is a very valuable—and rarely considered—property of the resonant current source (RCS).
Read the article…
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A resonant current source is a
series-resonant circuit having a
load in parallel to the resonant
capacitor. The circuit pushes
constant current into the load
regardless of its nature or
configuration. |
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The auxiliary power supply design
described here is based on the
SECO-HVDCDC1362-40W-GEVB
reference design with 15-V/40-W
continuous output power. |
Developing A 25-kW SiC-Based Fast DC Charger (Part 7): Auxiliary Power Supply Units For 800-V EV Chargers
by Karol Rendek, Stefan Kosterec, Didier Balocco, Aniruddha Kolarkar, Parthiv Pandya and Will Abdeh, onsemi, Phoenix, Arizona
In the 25 kW EV charger design presented in this series, an auxiliary PSU is used to power the controllers, drivers, communications components, and sensors of the submodules, while taking its input power directly from the dc link voltage. That’s generally 400 V or 800 V based on the car maker’s choice of battery. While 400-V batteries are currently dominant in the EV market, the trend is toward use of the higher-voltage, 800-V batteries. This article describes the design of an auxiliary PSU using a reference design that was developed for EV applications.
Read the article…
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FOCUS ON MAGNETICS
Sponsored by Payton Planar Magnetics
A monthly column presenting information on power magnetics design, products, or related technology |
A Simplified Winding Design Procedure For Transformers
by Dennis Feucht, Innovatia Laboratories, Cayo, Belize
An alternative transformer winding design procedure to that given in the references is presented here that is somewhat simpler and more like procedures typically found in textbook literature. In many cases this procedure should result in a sufficiently optimized design. It is iterative, minimizes eddy-current effects, and provides turns limits from static conditions. The rationale is to achieve a desired winding resistance Rw by using the eddy-current Dowell plots in reverse. Unlike more comprehensive procedures, no distinction is made between strands in turns bundles and windings without bundled strands. The total number of strands, whether bundled or not, is calculated from Dowell plot variables, wire size, and layers without regard to bundling or its effects on eddy-current behavior.
Read the full article…
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SPOTLIGHT ON SAFETY & COMPLIANCE
A monthly column discussing standards and regulatory requirements affecting power electronics |
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Comprehensive Reference On Transient Protection Includes Supercaps
Design of Transient Protection Systems Including Supercapacitor Based Design Approaches for Surge Protection, Nihal Kularatna, Alistair Steyn Ross, Jayathu Fernando and Sisira James, published by Elsevier, 2019.
Reviewed by James Spangler, Contributor, How2Power.com
The book is composed of ten chapters and five detailed appendices. The first chapter sets the stage for the rest of the discussion and suggests the scope of the book by providing a review of the different types of transients. These include voltage surges and power line disturbances such as sags and overvoltage conditions. Lighting surges are covered in discussions with various protection devices. Supercapacitors are introduced as a new way to absorb energy. Their ability to absorb electrical energy as a protection device is presented. This book would be useful for beginning engineers, experienced engineers as a review, and for engineers doing failure mode analysis.
Read the full story…
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 — POWER PRODUCTS IN 3 IMAGES OR LESS
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NEW ON HOW2POWER.COM
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For those interested in developments relating to space applications, there are numerous industry events where the latest technology and application requirements are discussed. For an overview of this year’s events including those providing information on space-grade power components and power converters, see How2Power’s recently updated “Space-Related Conferences and Trade Shows In 2022”.
The importance of batteries in vehicle electrification cannot be overstated, and they play a critical role in countless portable applications, small and large, as well as in energy storage. Each year the latest R&D and commercial developments are presented at dozens of industry events. How2Power’s recently updated “Battery-Related Conferences and Trade Shows in 2022” offers a listing of the 51 events spotted so far. Watch for updates and additions to this list throughout the year.
For more on various industry events that may be of interest to developers or users of power components and power converters of all kinds, see How2Power’s Industry Events section.
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 The 2022 IEEE VLSI Symposium on Technology & Circuits has announced its call for papers on the theme, “Technology & Circuits for the Critical Infrastructure of the Future”. Among the topics of interest are technical innovation and advances in “power, analog and mixed-signal devices, and circuits”.
TT Electronics has acquired the Ferranti Power and Control business from Elbit Systems for £9 million. Ferranti P&C is a U.K.-based manufacturer of power electronics and power systems for the aerospace and defense markets.
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