A High Step-Down Partial Power Processing Switched-Capacitor Converter for Wide Input Voltage Range Medium Voltage DC Applications

This article proposed a partial power processing switched-capacitor converter (P
³
SCC) for medium voltage dc applications, where a high-frequency switched-capacitor converter (HFSCC) operating in a series resonant state is used to transmit most of the power, and the remaining small power is regulated by a partial power processing phase-shift full bridge (P
⁴
SFB). Different from the conventional switched capacitors that use a dc bus to transfer energy from the highest voltage capacitor to the lowest voltage capacitor step by step, the P
³
SCC transfers power directly from each input capacitor to the load synchronously via the HFSCC, with uniform distribution of voltage and current stress, so the proposed one is more suitable for medium voltage high power conversion. Moreover, the P
⁴
SFB controls the HFSCC voltage amplitude by phase-shifting with the main power HFSCC, eventually regulating the output voltage, the main power is transmitted through only one resonant converter and soft switching of the main power
mosfet
s is achieved. The P
³
SCC has higher efficiency in medium voltage wide input range voltage regulation applications, since the P
⁴
SFB process half the current of the conventional partial power converter. A 1–1.6-kV dc input with 100-V dc/1 kW output prototype is built to verify the feasibility of the proposed topology.