Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences


UC Berkeley


Joint Colloquium Distinguished Lecture Series

Ultra-High Efficiency Grid-Connected Power Electronics for Distributed Photovoltaic Systems

Brandon Pierquet

Wednesday, March 21, 2012
306 Soda Hall (HP Auditorium)
4:00 - 5:00 pm

Brandon J. Pierquet
Senior Design Engineer, Enphase Energy


Social and economic forces, along with inherent limits in energy resources, are driving a need to reduce energy consumption and increase the use of renewable resources. Even modest reductions in the losses associated with the transmission and conversion of energy have a significant cumulative benefit, and play an essential role in meeting these goals. In particular, interest in photovoltaic (PV) systems has increased significantly over the past decade, and with the cost of modules continually dropping, more attention is being focused on how best to manage their integration to the grid while maximizing their energy capture ability. This talk will overview a system level comparison of traditional centralized inverter systems and more recent distributed conversion architectures, focusing on the growth of microinverters. The challenges facing these new low-power single-phase inverter designs will be investigated, emphasizing the energy storage requirement for delivering sinusoidal power to the grid, and the increasing need to achieve high-efficiency operation. In this context, a new single-stage resonant circuit topology will be presented that provides independent control over the energy storage voltage, soft-switching for all semiconductor devices, and full four-quadrant operation with the grid. Other applications of this design will be discussed, including its suitability for use in three-phase systems, solid-state lighting, and multi-port configurations. A brief discussion of alternative PV system architectures will also be included, including sub-module and cell-level configurations, to emphasize further opportunities for interfacing with both present PV materials, and those under development.


Brandon J. Pierquet received his Ph.D. and S.M. degrees in from the Massachusetts Institute of Technology in 2011 and 2006 respectively, and his B.S. degree from the University of Wisconsin-Madison in 2004, all in electrical engineering. After graduating M.I.T. he joined Enphase Energy as a senior design engineer. His research interests include resonant power conversion for ac systems, multi-port converter topologies, embedded system control, and solar energy applications.

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