Abstract: This paper introduces a novel PWM welding inverter with Zero-Voltage-Switching (ZVS) and Zero-Current-Switching (ZCS) phase shift full bridge.The lagging-leg switches are operated with ZCS for whole load ranges.It overcomes the limitation of the narrow zero-voltage ranges of the lagging leg in the convintional phase shift control inverter.The principle of the inverter and the experimental results are also presented.