A double-wing multilevel modular capacitor-clamped dc-dc converter with reduced capacitor voltage stress

This paper presents a double-wing multilevel modular capacitor-clamped (DW-MMCCC) dc-dc converter. Compared to the traditional single-wing (SW) MMCCC with the same voltage conversion ratio, the capacitor voltage stress of DW-MMCCC is reduced by half. And the switch and capacitor current stress, the switch voltage stress of the SW-MMCCC and the DW-MMCCC are the same. When the conversion ratio is equal to N, the total device and capacitor number of the even conversion ratio DW-MMCCC is 3N-2 and N, which is the same with the corresponding SW-MMCCC. The total device and capacitor number of odd conversion ratio DW-MMCCC is 3N-1 and N+1 respectively. By using the distributed stray inductance existing in the circuit, zero current switching (ZCS) can be achieved for all the switches of DW-MMCCC. And by using multi-phase DW-MMCCC, the input current ripple and input capacitor size can be reduced significantly. Compared with the traditional multilevel dc-dc converter, the power density of DW-MMCCC could be increased by about ten times. A 100 W three-phase 3X-ZCS-DW-MMCCC prototype has been built and tested. The simulation and experimental results are provided to verify the validity of the proposed converter.