WELDING POWER SUPPLY DEVICE

PROBLEM TO BE SOLVED: To provide a welding power supply device with less sputter, which uses a DC reactor DCL of a closed loop configuration.SOLUTION: The welding power supply device includes: a DC power supply circuit; an inverter circuit for turning a DC voltage to a high frequency AC voltage; a main transformer for attaining a voltage suitable for welding; a secondary rectifier circuit for rectifying the output of the main transformer; the DC reactor of a closed loop for smoothing the rectified output; an output current detection circuit for detecting an output current; a PID control circuit for inputting the output current and executing PID control; and a main control circuit for controlling the inverter circuit on the basis of PID control signals. The welding power supply device is provided with an inductance coefficient circuit for generating an inductance coefficient corresponding to the inductance value of the DC reactor and calculating the inductance coefficient on the basis of the output current, and the proportional gain, integration gain and differential gain of the PID control are changed based on the inductance coefficient in the PID control circuit to quicken the responsiveness of the PID control.