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Keeping Up with Advances in Capacitor Technology

March 6, 2020
In 2020, the PSMA celebrates the 35th Anniversary of its founding. This article is the next in a series highlighting the ongoing activities of its committees and forums that contribute to power-electronics and power-conversion tech advancement.

This article is part of the Power Management Series: Power Sources Manufacturers Association

Capacitors. These seemingly simple devices are an integral part of virtually every electronic design. It’s been noted that capacitors account for more items in most circuit bills-of-material (BOMs) than any other component. This is certainly true when it comes to power-conversion systems. And with the advent of higher-frequency power conversion, just as with magnetic components, a range of technical issues must be addressed in both the design and selection of capacitors.

The Power Sources Manufacturers Association’s (PSMA) Capacitor Committee and Forum has, for over a decade, worked to provide a reliable forum for information exchange and serve as a repository of the latest information. The work of the PSMA Capacitor Committee is all about providing the industry with the latest information and design insights.

To achieve this objective, the Committee develops and produces:

  • An Industry Session every year at the annual Applied Power Electronics Conference (APEC)
  • An all-day workshop on the Saturday before APEC.
  • A multi-part Capacitor Webinar series.

“In past years, capacitors have been seen as just passives with unfailing ability, but emerging technical developments are having a dramatic impact on capacitor selection and performance,” said Fred Weber of Future Technology Worldwide, Capacitor Committee Co-Chair. “The focus of our activities—the Pre-APEC 2020 Workshop, our Committee-sponsored Industry Session, and our Podcast Series—is to educate and enlighten engineers and interested users on how capacitors are contributing to meet the emerging industry needs for higher performance and reliability.”

Here’s a quick survey of the Capacitor Committee’s key ongoing activities:

Capacitor Webinars: From Leyden Jars to Supercaps

To date, the PSMA Capacitor Committee has produced three very informative webinars, available for download (see the link at the end of this article):

  • Capacitor Fundamentals – 101 (January 2019) Opening with the history of capacitors (starting with von Kleist’s Leyden Jars) and covering the fundamentals of capacitors, this first in the series covers the gamut of capacitor types (including film, electrolytic, multilayer ceramic, etc.) and common applications for capacitors in power applications.  
  • Capacitor Fundamentals – 201 (June 2019) Building on the earlier session, Caps 201 delves into modeling capacitors by defining equivalent series inductance and resistance (ESL and ELR) and how to de-rate capacitor specifications. Additional topics include a parameter review of polymer technology and a deep dive into a comparison of MLCC capacitor and film capacitor parameters.
  • Capacitor Fundamentals 301 (January 2020) In this third podcast of the series, “Strategies and Recommendations for Choosing Capacitors in Power Supply and Converter Applications,” the presenters dive into actual applications and discuss the pros and cons of which capacitor technology to use in each given situation and how to size that capacitor. The objective is to give the audience the necessary tools to aid them to make the best decisions as they develop their circuits.

Full-Day Workshops Offer Dive Deep into Application-Based Challenges

For the third year running, the PSMA Capacitor Committee, in collaboration with the IEEE Power Electronics Society (PELS) is producing a daylong workshop on the Saturday before the start of the Applied Power Electronics Conference (APEC). This year, the workshop will address specific needs of both beginners and advanced designers of dc-dc converters, frequency drives, inverters, and other power-conversion applications. The agenda covers application-based challenges rising from gallium-nitride (GaN) and silicon-carbide (SiC) topologies on capacitor technologies, the impact of the electrification of mobility services, as well as the latest capacitor developments (Fig. 1).

The 2020 Workshop will open with a keynote address titled, “Challenges and Requirements on Capacitors for Aircraft Electrification,” by Professor Pat Wheeler, PhD., Head of the University of Nottingham Power Electronics, Machines and Controls Group, and Global Director of the University’s Institute of Aerospace Technology. Workshop session presenters include experts from market-leading capacitor manufacturers, including KEMET, CDE, and Würth Elektronik, plus renowned lecturers from universities around the world. The technical lecture sessions will each be followed by a panel Q&A to offer attendees the opportunity to engage with the presenters (Fig. 2).

During breakfast, lunch, and the networking hour at the end of the workshop, attendees participate in interactive sessions of tabletop technology demonstrations addressing specific technical disciplines and capabilities consistent with the workshop agenda. Attendees at both the Capacitor and Magnetics workshops are invited to participate in these sessions.

APEC Capacitor Committee Industry Sessions Address Tech Challenges

Over the past several years, the PSMA Capacitor Committee has presented APEC Industry Sessions to bring capacitor theory, technology, and design principals into focus. These Industry Sessions combine presentations produced by capacitor manufacturers, academics, and industry experts. Here’s a list of the APEC Industry Session titles going back to 2012 (links to the individual presentation for all of these sessions are also available for free download):

  • APEC 2011 – Capacitors in Power Electronics
  • APEC 2013 – Advances in Capacitors and Ultracapacitors for Power Electronics
  • APEC 2015 – Applications Dictate Capacitor Technology
  • APEC 2017 – Capacitor Technologies for Evolving Power Electronic Applications
  • APEC 2018 – Capacitors for Emerging Power Conversion Applications
  • APEC 2019 – Design Considerations and A Deep Dive into Capacitor Technologies

Coming Soon – March 2020:

  • APEC 2020 – Capacitors That Stand Up to the Mission Profiles of the Future – e-Mobility, Broadband”

“With e-Mobility and Broadband on the horizon, capacitor technology needs to continually change to support higher frequencies and higher reliability,” commented Würth Elektronik’s Pierre Lohrber, PSMA Capacitor Committee Co-Chairman. “The latest technology will be the focus of our APEC 2020 Industry Session.”

Free Download of All Capacitor Committee Presentations and Workshops

As a service to the power-electronics design engineering community, all content created by and for the Capacitor Committee, including several years of APEC Industry Sessions, are available for download on the PSMA website—free-of-charge!

What Else is the Capacitor Committee Doing?

Finally, when asked about new activities, Wilmer Campanioni, representing KEMET and serving as Committee Co-Chair responded, “In addition to the on-going work in producing seminars, podcasts, and APEC Industry Sessions, the Capacitor Committee is also preparing to conduct a webinar as part of the PSMA Power Technology Roadmap series.”

The PSMA Roadmap project produces a biannual forward-looking report on expected developments in all aspects of power-conversion technology. The recently published 2019 edition is offered free-of-charge to PSMA members and available for purchase. Work is underway to produce the next edition in time for APEC 2021.

Invitation to be Part of PSMA

Since its founding in 1985, PSMA has strived to advance the interests of the power electronics industry through educational programs, technical forums, networking, conference sponsorships, and publications. Our industry’s power-conversion technologies and products are enabling many of the advances in today’s electrical infrastructure and electronics.

PSMA has grown thanks to the dedicated efforts of representatives from industry-leading companies and individuals. This article, presenting the activities of the PSMA Capacitor Committee, offers insights into the good work being accomplished through the voluntary contributions of PSMA members.

Member companies are afforded special benefits, including free copies of PSMA reports (often valued at several thousand dollars) and discounts at PSMA-sponsored events. More information about membership and benefits can be found at PSMA

Read more from the Power Management Series: Power Sources Manufacturers Association

Greg Evans, P.E., is Publicity Committee Co-Chair for the Power Sources Manufacturers Association.

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