A PFC Based Bridgeless Converter with Improved Power Quality for Welding Applications

A Power Factor Corrected (PFC) two stage, Bridgeless (BL) Cuk converter based switched mode power supply is proposed in this work for arc welding applications. The absence of input Diode Bridge Rectifier (DBR) reduces the conduction losses and improves the thermal utilization of the converter´s switches. The front-end comprises of a BL-Cuk converter operating in Discontinuous Conduction Mode (DCM) to attain unity Power Factor (PF) at the AC mains while at the back end, a PWM isolated Full Bridge (FB) DC-DC converter is used to regulate the output DC voltage. The performance of the system is examined in terms of the input PF, Total Harmonic Distortion (THD) of the ac mains current, voltage regulation and robustness. The obtained dynamic characteristics of this proposed topology depicts a constant voltage mode in various ranges of welding currents and inherent parametrical short circuit protection. Simulation results are presented to confirm the effectiveness of the proposed Arc Welding Power Supply (AWPS) in terms of excellent Power Quality (PQ).