Analysis and Optimal Design Considerations for an Improved Full Bridge ZVS DC–DC Converter With High Efficiency

This paper proposes an improved full bridge dc–dc converter, which can achieve zero-voltage-switching (ZVS) with wide input voltage range and load range. The operation principle of the converter and the optimal design considerations for high efficiency and ZVS range are analyzed. By adding two clamp diodes and two small coupled inductors at the primary side of the transformer, the voltage ringing across rectifier diodes is reduced. Therefore, Schottky diodes can be employed to reduce conduction loss, and high efficiency is achieved. A 1.2-kW/105-kHz prototype was made with an efficiency higher than 95% at full load to verify the theoretical analysis.