WELDING CURRENT CONTROL METHOD FOR INVERTER TYPE DC RESISTANCE WELDING MACHINE AND DEVICE THEREFOR

摘要

PURPOSE: To provide the welding current control method and device for the inverter type DC resistance welding machine capable of suppressing lowering of the output of a welding transformer and improving followability of a welding current for a target welding current waveform. ;CONSTITUTION: A differential absolute value arithmetic circuit 56 arranged to a welding controller 24 of the inverter type DC resistance welding machine differentiates the target welding current waveform outputted from a welding current waveform storage circuit 30 in the weld time, further, obtains an absolute value and outputs the arithmetic result to a frequency arithmetic circuit 58. The frequency arithmetic circuit 58 calculates frequency of triangular waves based on the differential absolute value and outputs this arithmetic result to a triangular wave generation circuit 46. Since frequency of a control pulse to generate the welding current is decided by frequency of the triangular waves, followability of the welding current for the target welding current waveform is decided by the differential absolute value of the target welding current waveform.;COPYRIGHT: (C)1994,JPO&Japio