Advanced Digital Control Techniques in Power Electronics - from Smartphones to Solar Photovoltaics

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Event Speaker: 

Prof. Robert Pilawa-Podgurski, University of Illinois, Urbana-Champaign

Event Location: 

Haus Room, 36-428

Event Date/Time: 

Friday, September 27, 2013 - 11:00am

Research Area: 

Abstract:
Thanks to the tremendous advancements of Moore’s Law, digital control has become a cost-effective option in power electronics, and is now gaining widespread adoption in industry. Digital control offers increased reconfigurability and flexibility, as well as improved robustness to process variations and temperature effects. Today, the most common power electronics solutions simply implement a standard analog feedback loop in the digital domain. Digital control, however, offers far more exciting opportunities than that; it enables entirely new control techniques that yield greatly improved performance. In this talk, I will present two such techniques, with applications in solar photovoltaics and low-voltage CMOS power delivery.

The first part of the talk will introduce Digital Dithering Ripple Correlation Control, a new control technique for maximum power point tracking in solar photovoltaics. By leveraging the existing ripple produced by dithering between adjacent duty ratios in a digital pulse-width modulator, we have experimentally demonstrated a 10x improvement in tracking speed/accuracy compared to the state-of-the-art, resulting in increased energy capture. The control technique is particularly well-suited for low-power, low-cost applications, and for emerging areas such as solar-powered mobile platforms.

In the second part, I will present a digital asymmetric interleaving technique for multi-phase power converters. We have shown that by adjusting the relative phase shifts between converters according to operating conditions, a significant ripple reduction can be achieved compared to conventional techniques. We will illustrate with an example of a low-voltage power management IC (180 nm CMOS) where a 2.5x reduction in input capacitance compared to existing solutions is possible. The technique shows great promise to reduce the size and cost of power converters used in portable electronics, where multiple independent voltage domains are used to power various parts of the system.

Bio:
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. In 2013, he received the Google Faculty Research Award for his work on data center power delivery. He is the co-author of two IEEE prize papers.