Two-Switch Forward Converter With Reset Winding and an Auxiliary Active-Clamp Circuit for a Wide Input Voltage Range

In this study, a two-switch forward converter with reset winding and an auxiliary active-clamp circuit for a wide input voltage range are proposed. The proposed converter offers simple reset scheme through reset winding, while retaining the reduced voltage stress on the switches. Hence, the operating duty ratio can be extended. Furthermore, it can also attain zero-voltage switching (ZVS) through the auxiliary active-clamp network when magnetizing inductor is properly designed. The operation principle of the proposed converter is analyzed. Analyses of the extended duty ratio and ZVS condition are then conducted in detail based on mode analysis. The performance of the proposed converter is evaluated using a 100-kHz 300-W/48-V prototype converter for an input voltage range of 200-400 V.