New half-bridge dc-to-dc converters for wide input voltage applications

This paper presents new soft-switched half-bridge dc-to-dc converters intended for applications where the input voltage varies widely. The proposed converters are presented in both non-isolated form and isolated form. The proposed dc-to-dc converters operate with zero voltage switching characteristics for MOSFET switches. The duty ratio of the proposed converter could expand to 100% and its voltage gain is twice the voltage gain of conventional half-bridge converters. Accordingly, the proposed converters are well suited for applications requiring high conversion efficiency at the presence of wide input voltage variations. The operation and performance of the proposed converters are demonstrated with experimental converters that deliver a 12 V/5 A output from a 35-60 V input. The non-isolated converter recorded the maximum efficiency of 91% at 1.5 A load current.