Massachusetts Institute of Technology

University of Colorado

Minjie Chen

David J Perreault

Khurram K Afridi

Steven B Leeb

Arthur Hsu Chen Chang

Benjamin J Montgomery

Saad Pervaiz

Curtis Serrano

Yu Ni

Described herein are power conversion systems and related techniques which utilize a coupled split path (CSP) circuit architecture. The CSP structure combines switches, capacitors and magnetic elements in such a way that power is processed in multiple coupled split paths in a variety of voltage domains. These techniques are well suited for power conversion applications that have one or more input/output ports that have a wide voltage range, or if the application is interfacing with the ac line voltage and requires power-factor correction.

Coupled split path power conversion architecture

A stacked switched capacitor (SSC) energy buffer circuit includes a switching network and a plurality of energy storage capacitors. The switching network need operate at only a relatively low switching frequency and can take advantage of soft charging of the energy storage capacitors to reduce loss. Thus, efficiency of the SSC energy buffer circuit can be extremely high compared with the efficiency of other energy buffer circuits. Since circuits utilizing the SSC energy buffer architecture need not utilize electrolytic capacitors, circuits utilizing the SSC energy buffer architecture overcome limitations of energy buffers utilizing electrolytic capacitors. Circuits utilizing the SSC energy buffer architecture (without electrolytic capacitors) can achieve an effective energy density characteristic comparable to energy buffers utilizing electrolytic capacitors. The SSC energy buffer architecture exhibits losses that scale with the amount of energy buffered, such that a relatively high efficiency can be achieved across a desired operating range.

Stacked switched capacitor energy buffer circuit

SSC energy buffer circuit includes a switching network and a plurality of energy storage capacitors. The switching network may operate at a relatively low switching frequency and can take advantage of soft charging of the energy storage capacitors to reduce loss. Efficiency of the SSC energy buffer circuit can be extremely high compared with the efficiency of other energy buffer circuits. The SSC energy buffer architecture exhibits losses that scale with the amount of energy buffered, such that a relatively high efficiency can be achieved across a desired operating range. Improvements in SSC energy buffer circuits include, in various implementations, the use of ground reference gate drive, the elimination of a separate precharge circuit through control of at least a portion of the switches of the SSC energy buffer circuit, and/or optimized ratio of capacitance values of two or more capacitors in an SSC energy buffer circuit.

A split drive transformer (SDT) and use of such a transformer in a power converter is described. The power converter includes a power and distributor circuit configured to receive one or more input signals and provides multiple signals to a first side of the SDT. The SDT receives the signals provided to the first side thereof and provides signals at a second side thereof to a power combiner and rectifier circuit which is configured to provide output signals to a load. In some embodiments, the SDT may be provided as a switched-capacitor (SC) SDT. In some embodiments, the power converter may optionally include a level selection circuit (LSC) on one or both of the distributor and combiner sides.

Switched-capacitor split drive transformer power conversion circuit

Enhanced stacked switched capacitor energy buffer circuit

Described is a method and apparatus for per-panel photovoltaic energy extraction with integrated converters. Also described are switched-capacitor (SC) converters have been evaluated for many applications because of the possibility for on-chip integration; applications to solar arrays are no exception. Also described is a comprehensive system-level look at solar installations, finding possibilities for optimization at and between all levels of operation in an array. Specifically, novel concepts include new arrangements and options for applying switched-capacitor circuits at 3 levels: for the panel and sub-panel level, as part of the overall control strategy, and for ensuring stable and robust interface to the grid with the possibility of eliminating or reducing the use of electrolytic capacitors.

Systems approach to photovoltaic energy extraction

Described herein is a stacked switched capacitor (SSC) energy buffer circuit architecture and related design and control techniques.

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Brighton, MA, United States of America

Minjie Chen