Power Electronics Seminar

Power Electronics Seminar hosted by Juan Rivas
Tuesday, February 3, 2015 - 4:00pm to 5:00pm
AllenX Auditorium
Prof. Robert Pilawa-Podgurski (University of Illinois Urbana-Champaign)
Abstract / Description: 

Today's society is seeing a rapid growth of distributed electric power sources and loads, with applications ranging from large grid-integrated photovoltaic installations and data centers to small implantable medical devices and portable electronics. These applications all require sophisticated electrical energy conversion, and the power electronics solutions that provide this must realize high efficiency, small physical size, and low cost.

In this talk I will discuss our recently developed techniques for improving the power density and efficiency of power electronics through a new hybrid switched-capacitor power conversion architecture and its associated control methods. The proposed architecture leverages the 100-1000x higher energy density of commercially available capacitors compared to inductors to achieve improved power density with maintained high efficiency. The fundamental loss mechanisms that have limited the performance of conventional switched-capacitor converters will be reviewed, as well as our proposed solution to overcome some of these limitations. A split-phase control method that achieves improved efficiency and power density will be presented, along with experimental validation using GaN-based converters ranging from tens to hundreds of volts and watts, operating at switching frequencies above 1 MHz, and power densities above 1011 W/in^3 (61.7 kW/L).

In the second part, I will present a power delivery architecture for extreme efficiency data centers. Through the use of a series-stacked structure with differential power processing converters, bulk power can flow without power conversion, and only differential power between servers is converted. This leads to extreme power efficiency, supported by the experimentally measured 99.8% record efficiency on our 4-server test-bed with real-world web server and computing loads. A quantitative comparison to a conventional 48 VDC power delivery architecture will be provided, showing a 40x reduction in power losses with our proposed method compared to state-of-the-art solutions.

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. He performs research in the area of power electronics. His research interests include renewable energy applications, energy harvesting, CMOS power management, and advanced control of power converters. Dr. Pilawa-Podgurski received the Chorafas Award for outstanding MIT EECS Master's thesis, 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 recieved the Air Force Office of Scientific Research Young Investigator Award. He is an associate editor of IEEE Transactions on Power Electronics, and IEEE Journal of Emerging and Selected Topics in Power Electronics, and is co-author of three IEEE prize