A modular converter for welding power supply with improved power quality

This paper presents a single-stage forward AC-DC converter for arc welding power supply. It is desirable to adjust various variables in welding process due to its complex nature. To improve the dynamic response of welding power supply, a three-phase modular power-factor-correction (PFC) converter is used to control a number of parameters, such as welding current, welding voltage, pulse duty cycle, arc striking current, short-circuit current, peak current etc. This topology is designed to operate in discontinuous conduction mode (DCM) to achieve inherent power-factor correction with reduced sensors. The design parameters of the welding power supply are determined to obtain the best achievable power factor with reduced THD (Total Harmonics Distortion) of AC mains current and voltage.