Soft Switching Active-clamp Dual-switch Flyback Converter

A novel active-clamp dual-switch flyback converter is proposed,which overcomes the disadvantage of high voltage stress on the main switch in conventional flyback converter.The main switches and auxiliary switch of the proposed converter all realize ZVS.Meanwhile,the rectifier diode on the secondary achieves ZCS.Additionally,the duty cycle can be extended to more than 50% by slope compensation.The converter makes full use of leakage inductor energy to achieve ZVS and does not use any snubber.Thus,it is favorable for high efficiency,wide input range capacity applications and is suited for the high input voltage occasions.The detail operation principles,characteristics and design principles are presented and the validity and applicability are also verified on a 127～330 V input,18.6 V/5 A output prototype.