OUTPUT CONTROL METHOD OF WELDING POWER SOURCE

PROBLEM TO BE SOLVED: To achieve balance of output current in each inverter circuit when a plurality of inverter circuits built in a power source unit are arranged in parallel, and parallel operation is performed. SOLUTION: In the output control method of a welding power source, N pieces of output control circuits are connected in parallel, and an output voltage set value Er for setting the output voltage of the welding power source, and an inductance set value Lr for setting a proper inductance value of the welding power source, are preliminarily set. A welding voltage during welding is detected and, simultaneously, a first output current of a first output control circuit or an N'th output current of an N'th output control circuit is detected. A current setting variance ΔIr=(Er-Vd)/Lr is calculated with a welding voltage detection value Vd as input, and a welding current control set value is calculated by integrating the current setting variance ΔIr, and a welding current command value is calculated by making the welding current control set value 1/N times. Then, the output is controlled in the manner that the first output current value of the first output control circuit or the N'th output current value of the N'th output control circuit is nearly equalized to the welding current command value. COPYRIGHT: (C)2010,JPO&INPIT