Inverting ZCS switched-capacitor bi-directional converter

The proposed inverting type zero-current switching switched-capacitor (ZCS SC) DC/DC converters are a new type of bi-directional power flow control conversion schemes. They possess high efficiency, low EMI emission and current stress features for the proposed quasi-resonant switched-capacitor inverting converters. A family of inverting type zero-current switching switched-capacitor bi-directional converters is presented, which can improve the current stress problem during the bi-directional power flow control processing. They are able to provide voltage conversion ratios from −1 /−1 (inverting unit-mode/inverting unit-mode) to −n /−1/n (inverting n-mode/inverting 1/n-mode) by using four power MOSFET main switches and a set of switched-capacitors, series connected with a small resonant inductor. The principle of the converter operation of the proposed bi-directional power conversion scheme is described in detailed circuit model analysis. Simulation and experimental results are carried out to verify the validity and the soft switching performance of the proposed inverting ZCS SC bi-directional DC/DC converters. The maximum efficiency can achieve about 93.1% and 94.8% for the forward and reverse power flow control schemes, respectively.