Analysis and design of a current-fed zero-voltage-switching and zero-current-switching CL-resonant push-pull dc-dc converter

A current-fed zero-voltage-switching (ZVS) and zero-current-switching (ZCS) CL-resonant push-pull DC-DC converter is presented in this paper. The proposed push-pull converter topology is suitable for unregulated low-voltage to high-voltage power conversion with low ripple input current. The resonant frequency of both capacitor and inductor is operated at approximately twice the main switching frequency. In this topology, the main switch is operated under ZVS because of the commutation of the transformer magnetising current and the parasitic drain-source capacitance. Because of the leakage inductance of the transformer and the resonant capacitance from the resonant circuit, both the main switch and output rectifier are operated by implementing ZCS. The operation and performance of the proposed converter has been verified on a 400-W prototype.