A new three-level soft-switched converter

A three-level, constant-frequency, isolated converter which employs a coupled inductor to achieve zero-voltage switching (ZVS) of the primary switches in the entire line and load range is described. Because the coupled inductor does not appear as a series inductance in the load current path, it does not cause a loss of duty cycle or severe voltage ringing across the output rectifiers. The operation and performance of the proposed converter was verified on a 1-kW prototype.