Power Electronics Seminar Series

UC Berkeley IEEE PELS-IAS Student Chapter hosts the Power Electronics Seminar Series, a seminar series featuring speakers from academia and industry. If you are interested in speaking at a future seminar event, please contact our Officers at pels@lists.eecs.berkeley.edu.

Upcoming Events

Stay tuned for upcoming events!

Past Events

Prof. Philip Krein January 23, 2019
Dr. Eyal Aklimi August 27, 2018
Mahima Gupta April 11, 2018
Dr. Michael Seeman February 21, 2018
Prof. Robert Pilawa-Podgurski July 13, 2017 (co-hosted with SFBAC IEEE PELS)
Prof. Jose A. Cobos March 22, 2017
Prof. Seth Sanders November 17, 2016 (co-hosted with SFBAC IEEE PELS)
Dr. Pradeep Shenoy October 27, 2016 (hosted by SFBAC IEEE PELS)
Prof. Juan Rivas-Davila September 29, 2016 (co-hosted with SFBAC IEEE PELS)
Dr. Leo Casey February 17, 2016
Prof. Dragan Maksimovic February 1, 2016
Prof. Junrui Liang December 8, 2015
Prof. Juan Rivas-Davila November 4, 2015

Making Solar Energy Economical – How Startup Companies Have Disrupted Renewable Energy

Event Details

Wednesday, January 23, 2019
Room 380, Soda Hall, UC Berkeley (Directions)
3:00 - 4:00 PM

Prof. Philip Krein

Executive Dean
Zhejiang University/University of Illinois at Urbana-Champaign Institute

Abstract: How can solar energy become the most important sustainable resource to meet fast-growing demand? Only a few years ago, solar energy was much more expensive than more conventional resources. Today, it is much cheaper and still dropping in cost. What changed? This talk describes the experience from a startup company perspective, considering how solar energy has been disrupted completely over the past 15 years. A special perspective is given from one company that introduced a technology cutting solar energy costs in half. The talk covers both the underlying challenges of low-cost solar power and the engineering realities of a small company driving big change. The progression from early ideas and inventions to working products and sales is described. The discussion outlines what it takes to get dramatic new results in technologies, and also in markets. The underlying problems include making completely new products, proving them out for use by millions of customers, and building the market links that get them to customers.

Biography: Philip T. Krein was co-founder and Chairman of the Board of Solarbridge Technologies from its founding in 2003 through its acquisition by Sunpower in 2014. He holds 42 U.S. patents and six European patents, many of them linked to the modern ac solar panel developed by Solarbridge. He is a member of the U.S. National Academy of Engineering, a fellow of the U.S. National Academy of Inventors, a fellow of IEEE, a foreign expert under the China 1000 Talents Program, and a recipient of the IEEE William E Newell Power Electronics Award. He is a past president of the IEEE Power Electronics Society, a past chair of the IEEE Transportation Electrification Community, and Executive Dean of the Zhejiang University/University of Illinois at Urbana-Champaign Institute. He is the Grainger Endowed Emeritus Chair Professor in Electric Machinery and Electromechanics at the University of Illinois and is a Distinguished Professor at Zhejiang University.

Topics in Power Electronics: Limitations to Miniaturization of Magnetic Inductors and High Frequency Face-to-Face Bonded Si-GaN converter

Event Details

Monday, August 27, 2018
400 Cory Hall, University of California, Berkeley

Dr. Eyal Aklimi

Lead Electrical Engineer, Vium, Inc.

Abstract: Magnetic components pose particular challenges to miniaturization, efficiency, and frequency of power electronics systems. Converters are expected to shrink and increase in power density, while maintaining excellent efficiency, supporting sophisticated energy-saving techniques such as voltage scaling (DVS), and enabling deeper and faster PDNs. In this talk I will present the state-of-the-art in miniaturization of magnetic components for integrated voltage regulators: fabrication techniques, materials, and designs. Particular emphasis will be laid on the inclusion of magnetic materials in inductor topology. While smaller magnetic components promote smaller and faster converters, integration still remains a limiting factor. Better integration is a key enabler for capitalizing on many improvements to individual converter components. I will present a recent demonstrator of a 40MHz non-monolithic, tightly-integrated voltage regulator. The architecture that enables such performance includes fine-line Si circuitry, face-to-face bonded with GaN halfbridge switches.

Biography: Eyal Aklimi has over 15 years of professional experience, most recently he is the Lead Electrical Engineer for Vium, Inc., a biotech company in San Mateo, CA. Prior to Vium he was the Lead Electronics Innovator at Diamond Nanotechnologies, an R&D start-up in Boston, MA. Eyal holds a Ph.D. in Electrical Engineering from Columbia University and B.Sc. in Electrical Engineering and Physics from Tel-Aviv University. Eyal has been published in several scientific journals that recognizes his innovations in electrical engineering, power electronics and magnetism. Eyal is avid contributor and presented to academic and industry conferences. Eyal was also a co-founder of Jux (currently YCD-Atmosphere), a multi-million dollar media distribution algorithms company.

Robust Control of High Density Cascaded DC Voltage Link Power Converters

Event Details

Wednesday, April, 11, 2018
540AB Cory Hall, University of California, Berkeley

Mahima Gupta

Ph.D. Student, University of Wisconsin, Madison

Abstract: Cascaded power conversion systems with a bulky DC link are used in most electric traction applications, industrial motor drives, renewable energy systems, uninterruptable power supplies, etc. The voltage across this intermediate DC link is typically maintained at a nearly constant level and is a critical prerequisite to using the classical pulse width modulation (PWM) and proportional-integral regulation (PI) techniques to obtain the desired power conversion with adequate fidelity. In these cases, the dc link capacitor is sized to store enough energy to maintain several tens of cycles of ac output at the rated power. This large amount of energy storage at the DC link is realized by utilizing bulky electrolytic capacitors in the range of 100µF-3000µF which can occupy as much as 60-70% of the converter volume.

On the other hand, the concepts presented in this talk are primarily aimed to maintain a stiff dc bus as well as synthesize high quality waveforms, but without employing large energy storage. The proposed approach determines the switching intervals of the various solid state switching devices in an integrated fashion and places them in a particular sequence determined by the desired voltage and current waveforms, using an intelligent controller. Moreover, the robust controller uses the proposed concept of capacitor charge restoration to maintain DC link stiffness without large amounts of energy storage. There are several advantages of implementing this idea. The size of the required DC link bulky capacitor can be reduced by several orders of magnitude ( 10µF against 100µF-3000µF). The resulting significant reduction in the size of the capacitive reactive components in emerging applications, opens the prospect of replacing electrolytic capacitors that have a limited life span with film capacitors with much longer life. Several case studies, along with results from simulation and a preliminary experimental prototype validate the proposed approach.

Biography: Mahima Gupta received her B.E. degree in Electrical and Electronics Engineering from Birla Institute of Technology and Science, Pilani, India (BITS-Pilani). She completed her M.S. degree in Electrical and Computer Engineering from University of Wisconsin, Madison, USA (UW-Madison) in 2015, where she is currently working towards a Ph.D. degree. She is currently a Research Assistant and is affiliated with the Wisconsin Electric Machine and Power Electronics Consortium (WEMPEC). Mahima’s research interests include power electronics and their applications, motor drive systems and electrical machines.

Eta Designer Software Demo and Tutorial

Event Details

Wednesday, February, 21, 2018
433 Cory Hall, University of California, Berkeley

12-1pm: Demo and Tutorial

Lunch Provided!

Michael D. Seeman, Ph.D.

President and Founder, Eta One Power, Inc.

Abstract: Eta One Power, Inc. is a Silicon Valley based startup developing the next-generation of electronics CAD/analysis software.

Biography: Dr. Michael Seeman is the President and Founder of Eta One Power, an engineering software startup company. Eta One Power is the company behind Eta Designer, the first simulation and analysis software that focuses on increasing power density and efficiency of power supplies. His focus is on the analysis and computational optimization of tradeoffs in power converter design.

He was formerly the Systems and Applications Engineering Manager in the Gallium Nitride Products Group at Texas Instruments. He has significant experience in cutting-edge power conversion solutions using wide-bandgap technologies, resonant converter architectures and modern magnetics structures. He previously worked in two Silicon Valley startups in the power electronics space.

Michael received his S.B. degree from the Massachusetts Institute of Technology and his M.S. and Ph.D. degrees from UC Berkeley. He is a member of the IEEE and the vice-chair for the SF Bay Area Chapter of PELS.

Extreme Power Density Converters ‐ Fundamental Techniques and Selected Applications

Event Details

Thursday, July 13, 2017
Texas Instruments, Building E Auditorium, 2900 Semiconductor Dr, Santa Clara, CA 95051

6:30-7p: Registration, Dinner and Networking
7-8pm: Talk

Prof. Robert Pilawa-Podgurski

University of Illinois, Urbana-Champaign

Abstract: Today's society is seeing a rapid transition from fossil-fuel power sources to an electric grid powered from renewable energy. Likewise, electrification is making significant in-roads in the transportation sector, owing to the increased performance, reduced operating costs, and environmental benefits from electric drive systems. In both areas, power electronics is used for efficient conversion of electric energy and is a key enabling technology.

In this talk I will present our recently developed techniques for drastically improving the fundamental power density and efficiency of power electronics through a new class of hybrid switched-capacitor power converters. An example 2 kW solar photovoltaic inverter prototype from the Google-IEEE Little Box Challenge will be presented to illustrate the achievable performance improvements over conventional techniques, yielding the highest power density (216 W per in^3) published to date by any group. A second example application - electric aircrafts - will demonstrate how lightweight power electronics can enable an entirely new class of low-emission, low-noise airplanes. Designs principles and hardware results from an 18 kW/kg motor drive will be provided.

Biography: Robert Pilawa-Podgurski received dual B.S. degrees in physics, electrical engineering and computer science in 2005, the M.Eng. degree in electrical engineering and computer science in 2007, and the Ph.D. degree in electrical engineering in 2012, all from the Massachusetts Institute of Technology.

He is currently an Assistant Professor in the Electrical and Computer Engineering Department at the University of Illinois, Urbana-Champaign, and is affiliated with the Power and Energy Systems group. His research interests include renewable energy applications, electric transportation, CMOS power management, and advanced control of power converters. Dr. Pilawa-Podgurski received the Google Faculty Research Award in 2013, and the 2014 Richard M. Bass Outstanding Young Power Electronics Engineer Award of the IEEE Power Electronics Society, given annually to one individual under age 35 for outstanding contributions to the field of power electronics. In 2015, he received the Air Force Office of Scientific Research Young Investigator Award, and in 2016 the UIUC Dean's Award for Excellence in Research. He is most proud of his numerous teaching distinctions based on student evaluations. He is an associate editor of IEEE Transactions on Power Electronics, and IEEE Journal of Emerging and Selected Topics in Power Electronics, and has co-authored six IEEE prize papers in the last four years.

The Google “Little Box Challenge” - Energy Efficiency through Power Electronics @ CEI-UPM

Event Details

Wednesday, March 22, 2017
Room 540AB, Cory Hall, UC Berkeley (Directions)
12:00 - 1:00 PM

Prof. Jose A. Cobos

Centro de Electrónica Industrial
Technical University of Madrid (UPM)

Abstract: Power Electronics is a key enabler for Energy efficiency. The recent improvements in GaN power switches and a novel methodology to evaluate power architectures are illustrated through the participation of the team CEI@UPM in the “Little Box Challenge” (Google and IEEE-PELS). The talk begins with an overview of several projects and activities developed for Industry partners at CEI-UPM, including RF amplifiers, PV panels, wireless power transfer, ripple based control in IVR for Digital Systems and AC-DC & DC-DC converters for the high voltage bus (270Vdc) more electric aircraft. Finally, the “Industrial Council @ CEI” is briefly described.

Biography: José A. Cobos is a Full Professor at the Universidad Politécnica de Madrid and Chair of the “Industrial Council @ CEI”. He lectures Electronics with special focus on Fundamentals, Analog, and Power Electronics, for Undergraduate, Master and Doctoral students.

His contributions are focused in the field of power supply systems for telecom, aerospace, industrial, automotive, renewable energy and medical applications. His research interests include energy efficiency in digital systems and RF amplifiers, magnetic components, piezoelectric transformers, transcutaneous energy transfer and dynamic power management. He also works in the generation of EM fields for water supercooling and biomedical effects. He advised over 40 Master Thesis and 14 Doctoral dissertations, published over 50 journal papers and over 300 technical papers and holds 8 patents. He conducted professional seminars and tutorials in USA, UK, Austria, Germany, Italy, Sweden, Switzerland, Syria, Mexico and Macedonia.

In 2006, he launched the “Centro de Electrónica Industrial, CEI-UPM”, a University research center leading a strong industrial program in power electronics and digital systems. In 2016 he launched the “Industrial Council @ CEI” to coordinate Education & Research with Industry, and provide scholarships to CEI students, sponsored by Airbus S&D – CRISA, Thales Alenia Space, Bosch, Premo, Huawei, Indra, Ansys, Viesca, Airbus and Apex. He has been RCC Fellow at Harvard University and recipient of a Fulbright grant to work on Energy Efficiency, at UC Berkeley.

Flywheel Energy Storage: The Utility Scale Energy Storage Solution

Event Details

Thursday, November 17, 2016
ON Semiconductor, 3001 Stender Way, Santa Clara, CA 95054

6:30-7p: Registration, Dinner and Networking
7-8pm: Talk and Questions

Prof. Seth Sanders

UC Berkeley

Abstract: Energy storage is now emerging as an essential electric utility resource to effectively enable higher penetration levels of variable renewable generation resources. In California, in response to RPS mandates for increased renewable penetration, Assembly Bill 2514, in conjunction with CPUC rulings, has called for 1.3 GW of flexible energy storage to be incorporated into the energy mix by the three California IOUs during the next few years. Similar actions are being followed in other U.S. states, and worldwide. The talk will review the energy storage landscape, and then focus on the speaker's interests in advancing flywheel energy storage to meet utility scale challenges. In short, a flywheel functions as a battery, with kinetic energy storage replacing conventional electrochemical processes. Based on numerous implementations and products released during the past 20-30 years, there has been a general belief in the power systems community that flywheels are only suited to short term applications, for example in frequency regulation, grid stability enhancement, voltage support, and in UPS and transit system applications. This is not the case, and the talk will outline how flywheels can be economically designed to meet multi-hour energy shifting applications, that are essential for provision of capacity, and extended integration of variable renewable generation. Some details on product and project development at grid scale energy storage start-up Amber Kinetics will be discussed.

Biography: Seth R. Sanders is Professor in the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley. He received S.B. degrees (1981) in Electrical Engineering and Physics, and the S.M. (1985) and Ph.D. (1989) degrees in Electrical Engineering from the Massachusetts Institute of Technology, Cambridge. Following an early experience as a Design Engineer at the Honeywell Test Instruments Division in 1981-83, he joined the UC Berkeley faculty in 1989. Dr. Sanders is co-founder and Chief Scientist of Amber Kinetics, Inc., a technology developer, manufacturer, and project developer of utility scale flywheel energy storage systems. His technical interests are in electrical energy and power conversion systems. Dr. Sanders is presently or has recently been active in supervising research projects in the areas of flywheel energy storage, high frequency integrated power conversion circuits, IC designs for power conversion applications, electric machine design, and renewable energy systems. During the 1992-1993 academic year, he was on industrial leave with National Semiconductor, Santa Clara, CA. Dr. Sanders received the NSF Young Investigator Award and multiple Best Paper Awards from the IEEE Power Electronics and the IEEE Industry Applications Societies. He has served as Chair of the IEEE PELS Technical Committee on Computers in Power Electronics, Chair of the IEEE PELS Technical Committee on Power Conversion Components and Systems, and as Member-At-Large of the IEEE PELS Adcom. He is an IEEE Fellow, a Distinguished Lecturer of the IEEE PELS and IAS societies, and recipient of the IEEE PELS Modeling and Control Technical Achievement Award.

The Technology behind the World's Smallest 12V, 10A Voltage Regulator

Event Details

Thursday, October 27, 2016
Texas Instruments, Building E Conference Center

6:30-7p: Registration, Dinner and Networking
7-8pm: Talk and Questions

Dr. Pradeep Shenoy

Texas Instruments

The Continued Potential of Increased Grid Electronics

Event Media

Event Details

Wednesday, February 17, 2016
Room 405, Soda Hall, UC Berkeley (Directions)
4:00 - 5:30 PM

Dr. Leo Casey

Power Architecture Lead Engineer

Abstract: Electronics are ubiquitous in our lives and their effects and impacts are pervasive. Meanwhile, our Grid, which transports almost half of our overall energy, has almost no electronics in the physical layer. While the instrumentation and control layers have become increasingly electronic, with distributed PMUs and smart meters, the T&D system has not changed significantly since the times of Edison, Tesla and Westinghouse. We will review those changes, the impacts that electronics do have in the modern grid and the remaining potential for improved reliability and resilience from increasing utilization of electronics in the Grid, particularly power electronics in the physical layer.

Biography: Dr. Leo Casey is the Power Architecture Lead Engineer at Google-X. Prior to that, he was Satcon’s Chief Technology Officer and EVP of Engineering. He has over 30 years of experience in power electronics and power engineering, including ultimate responsibility for the design and commercialization of numerous utility scale power conversion products such as Inverters, Solid State Switches, Converters, and Flywheels, with a focus on the management and integration of alternative, renewable and distributed resources. He has served on NREL’s solar advisory board and the NIST/DOE Hi-MW Leadership Committee; been an editor of the IEEE Transactions on Energy Conversion; and is active in IEEE and NEC code and standard development for Grid Electronics. Dr. Casey has published over 75 papers related to power conversion and Grid Power Electronics, and made many presentations at industry workshops and conferences.

Monolithic High Frequency GaN Switched-Mode Power Converters

Event Media

The slides from the talk are available here.

Event Details

Open to the public! Dinner will be served.

Monday, February 1, 2016
Room 540AB, Cory Hall, UC Berkeley (Directions)
6:00 - 7:30 PM

Dr. Dragan Maksimovic

ECEE Department
University of Colorado, Boulder

Abstract: This seminar is focused on monolithic integration and optimization of switched-mode power converters in wide bandgap gallium-nitride (GaN) processes. It is shown how superior device and process characteristics in combination with soft switching and integration techniques can lead to improvements in efficiency, power density and dynamic responses. Very high frequency (10-400 MHz) power converters will be presented based on custom GaN chips with integrated power switches and gate drivers, allowing standard logic-level PWM control inputs. Operating from up to 50 V dc input voltage, efficiencies exceeding 90% are demonstrated at switching frequencies up to 100 MHz and at power levels exceeding 10 W. Application examples include envelope-tracking drain supply modulators for high-efficiency RF transmitters.

Biography: Dragan Maksimovic received B.S. and M.S. degrees from the University of Belgrade (Serbia, Yugoslavia), and his Ph.D. degree from the California Institute of Technology, Pasadena, in 1989. Since 1992, he has been with the University of Colorado at Boulder, where he is currently a Charles V. Schelke Endowed Professor and Director of the Colorado Power Electronics Center (CoPEC). He has co-authored over 250 papers and the 2nd edition of the textbook Fundamentals of Power Electronics. Prof. Maksimovic is a Fellow of the IEEE. His current research interests include power electronics for renewable energy sources and energy efficiency, high frequency power conversion using wide bandgap semiconductors, digital control of switched-mode power converters, as well as analog, digital and mixed-signal integrated circuits for power management applications.

Piezoelectric energy harvesting technology and its power conditioning designs

Event Media

The slides from the talk are available here.

Event Details

Open to the public! Dinner will be served.

Tuesday, December 8, 2015
Room 540AB, Cory Hall, UC Berkeley (Directions)
6:00 - 7:30 PM

Dr. Junrui Liang

Assistant Professor
School of Information Science and Technology
ShanghaiTech University, Shanghai, China

Abstract: Piezoelectric energy harvesting (PEH) systems are designed for future distributed and mobile electronics, with the purpose to make these devices energy self-sufficient by scavenging the vibration energy in their ambience. A power conditioning circuit connects the piezoelectric transducer and the dc load; therefore it plays an indispensable role towards practical applications. Moreover, by intervening the power conversion process with the synchronized switch (also called bias-flip) scheme, the power conditioning circuit can enhance the system-level electromechanical coupling and, as a result, increase the harvested power by several hundred percent, at the same time, significantly damped the vibration. This talk reports the state of the art and our contribution on piezoelectric power conditioning circuits towards better understanding, design, and future development of PEH systems.

Biography: Dr. Junrui Liang has received his PhD degree in Mechanical and Automation Engineering from The Chinese University of Hong Kong, China, in 2010. He is now an Assistant Professor at the School of Information Science and Technology, ShanghaiTech University, China; and also a Visiting Scholar at the EECS Department, UC Berkeley. Since his student period, Dr. Liang has devoted himself to the interdisciplinary researches on mechatronic energy conversion systems. He has developed efficient harmonic based analysis and optimization for some power conversion systems such as the class-E resonant inverters and piezoelectric energy harvesting systems. He has also made innovative power conditioning circuit designs towards more capable piezoelectric energy harvesters. Dr. Liang has published more than 20 peer-reviewed technical papers on international journals and conferences and received four research awards. He is a member of IEEE and ASME, reviewer of about 20 international journals and conferences, and a section chair and program committee member of SPIE Smart Structure/NDE international conference.

Power Electronics in the SUPER-Lab (Stanford University Power Electronics Research – Laboratory)

Event Media

The slides from the talk are available here.

Event Details

Open to the public!

Wednesday, November 4, 2015
Room 540AB, Cory Hall, UC Berkeley (Directions)
6:30 - 8:00 PM


  • 6:30 - 7p: Informal networking and pizza

  • 7 - 8p: Seminar talk

  • 8p: Adjourn

Dr. Juan Rivas-Davila

Assistant Professor
Department of Electrical Engineering
Stanford University

Abstract: Power supplies are everywhere from consumer electronics, to medical imaging systems, to military systems. Modern applications demand power supplies that are efficient, lightweight, and with fast dynamic characteristics. Conventional power electronic designs, because of their operating frequency can be large, and expensive if design to meet high performance specifications. A new generation of power electronics based on very high switching frequencies is providing energy savings, reduced component size, and new fabrication options that can lead to low cost designs. As an added benefit, such designs can enable operation in harsh environments, space, and open the door to some exciting new applications for power electronics that will be discussed during the talk.

Biography: Professor Juan Rivas joined the EE faculty at Stanford University in January 2014. He comes to Stanford after two and a half years as a faculty in the EECS Department at the University of Michigan. Prior to starting his work in academia, he worked for the General Electric Global Research Center developing power electronics for medical imaging and aviation systems. Professor Rivas has extensive experience in the design of dc-dc power converters working at MHz frequencies. He has published peer reviewed work describing power converters reaching up to 110 MHz switching frequencies using conventional silicon devices. While at MIT, he was part of the MIT-Industry Consortium on Advanced Automotive Electrical-Electronic Components and Systems, as well as a member of the team working on DARPA RIPE (Robust Integrated Power Electronics).