It　is　very　difficult　for　arc　welding　inverter　to　realize　Zero-Voltage-Switching　(ZVS)　because　the　load　of　arc　welding　inverter　changes　violently.　An　improved　PS-FB-ZVS-PWM　(Phase-Shifted　Full-Bridge　Zero-Voltage-Switching　Pulse-Width-Modulation)　topology　is　proposed　in　this　paper.　A　saturate　resonant　inductor　is　in　series　with　the　primary　side　of　the　transformer,　while　an　auxiliary　inductor　is　in　parallel　with　the　secondary　side　of　the　transformer　to　increase　reactive　current　in　light　load　or　unload　state,　so　the　zero　voltage　switching　of　power　devices　is　realized　during　switching　course　in　light　load　or　unload　state.