The paper presents a novel ZVZCT softswitching PWM converter:the voltage and current waveforms of the transistor are laddershaped and stagger each other,and auxiliary switches are turned on and off under zero current.It is very attractive for high power application where IGBT is predomi nantly used as the power switches.Theoretical analysis,parameters selection,comp uter simulation,and experiment results are presented to explain the proposed sch eme.