A novel ZVZCS full-bridge PWM DC-DC converter with active voltage clamp and energy recovery circuit

An improved zero voltage and zero current switching (ZVZCS) full-bridge (FB) PWM DC-DC converter is proposed. The new converter overcomes drawbacks such as voltage ringing and voltage overshoot in conventional ZVZCS converter. An auxiliary circuit consists of auxiliary switcher, clamping capacitor, diode rectifier and energy recovery transformer. The auxiliary circuit alleviates the voltage ringing and voltage overshoot in secondary side of transformer and recovers the energy absorbed by clamping capacitor to the power supply in primary side. Because the auxiliary circuit is shunt to main circuit, the energy loss is very small so high efficiency of the converter is achieved. Synchronizing rectifier is used in secondary side of transformer so this converter is very attractive to low voltage, high current application. The operation, analysis, and design consideration are illustrated and verified on a 1 kW 100 kHz IGBT based experimental circuit.