Power quality improvement using three phase modular converter for welding power supply

This paper deals with the power quality improvement in an arc welding apparatus. An efficient arc welding process needs fine and fast dynamic control of energy flow for good weld quality and productivity. The existing welding machines have the problem of low power factor and high harmonic content at the utility interface. A three-phase modular power-factor-correction converter connected to a pulse width modulated DC-DC converter is proposed for welding power supply. The full-bridge modular converter provides attractive features such as inherent power factor correction, simple DC-DC switching control, high frequency transformer isolation and single-stage power conversion. The converters are designed to operate in both CCM and DCM operation in different power ratings. The proposed system significantly improves the dynamic response of the converter. The criteria for obtaining high power factor is being analyzed and the circuit parameters are determined to obtain the best achievable power factor with reduced THD (Total Harmonics Distortion) of AC mains current and voltage.