A Zero-Voltage and Zero-Current Switching Interleaved Two-Switch Forward Converter With Passive Auxiliary Resonant Circuit

This article presents an interleaved two-switch forward dc/dc converter with zero-voltage and zero-current switching, which adopts a coupled inductor and a snubber capacitor. The proposed converter can realize soft operation for main power switches by using the coupled inductor, snubber capacitance, the leading switches' parallel capacitances, and the transformer leakage inductance. Compared with the initial converter that uses a coupled inductor, during the freewheeling stage, the proposed converter has significant performance in reducing the primary circulating current that flows through the power elements. More importantly, the proposed converter can eliminate the problems in the rectification diodes such as voltage stress, parasitic ringing, and reverse recovery. Based on the equivalent circuits in different operation modes, the operation principle and the soft-switching requirement of the converter are discussed. Besides, the design criteria for the key parameter are given in this article. The practical effectiveness of the proposed converter was validated by the simulation results and experimental results of prototype using the power mosfet.