Full digital control strategy of double pulsed MIG/MAG welding

Based on a wire feed at periodically varying, to make arc length constant and the welding process stable, a triple closed loop control model composed of arc length regulation, instantaneous voltage and current feedback is established for double pulsed MIG/MAG welding. Arc length can be detected and regulated during each droplet transfer. To keep the arc length constant, stick-out can also be compensated for keeping arc length constant. The proposed model is implemented with DSP and experimental results of a prototype showed that the welding process with the proposed control strategy is stable and the welding appearance is perfect.