A New ZVS DC/DC Converter With Three APWM Circuits

This paper presents a new soft-switching dc/dc converter with series-connected transformers to implement the features of zero-voltage switching (ZVS), load current sharing, low voltage stress for MOSFETs, and low current rating for the rectifier diodes and the output inductors. The proposed converter includes two half-bridge circuits connected in series to limit the voltage stress of MOSFETs at one-half of the input voltage. The output sides of the two circuits are connected in parallel to reduce the current rating on the rectifier diodes and the output inductors and to achieve load current sharing. In order to balance two output inductor currents, series-connected transformers at the low-voltage side are adopted. Thus, the output power is equally distributed by the two half-bridge circuits. The output capacitances of MOSFETs and the resonant inductances are resonant at the transition instant such that MOSFETs can be turned on at ZVS. Finally, experiments based on a laboratory prototype with 1-kW rated power are provided to demonstrate the performance of the proposed converter.