Switched Capacitor Converter with Flexible Voltage Gain and 99.2% Efficiency Utilizing Autotransformer

This paper presents a novel topology for bidirectional power transfer between an Energy Storage System and a DC Microgrid. The topology provides a cost-effective, high-efficiency approach to extend the voltage gain range of a switched capacitor converter with only addition of an autotransformer. The proposed non-isolated topology is derived from an isolated dual active bridge (DAB) converter. In which, the flexible voltage gain is realized by selecting of the turn's ratio of an autotransformer with bidirectional phase-shift modulation. A 30 kW prototype is designed, manufactured, and tested. It has verified the operating principle of the proposed converter with 99.2% peak measured power conversion efficiency.