Power quality improved SMPS using BL-CSC converter for welding applications

In this paper, a single-phase power quality improved switched-mode power supply (SMPS) using bridgeless (BL) canonical switching cell (CSC) converter is analyzed, designed and experimentally tested for welding applications. The elimination of diode bridge rectifier (DBR) at the input leads to reduced conduction losses and high power density thereby improving thermal management. BL-CSC converter functions in discontinuous inductor current mode (DICM) to naturally realize high power factor (PF) with low total harmonic distortion (THD) in the input current. Other benefits include simple control circuitry, high efficiency and low electromagnetic-interference noise. BL-CSC converter is then connected to isolated full bridge (FB) converter modules, which are arranged to increase the overall current rating of the proposed arc welding power supply (AWPS). The controller for the proposed AWPS aims to regulate the DC voltage at the output as well as to limit the current at the load end, so as to make it suitable for welding applications. Theoretical analysis and experimental results for a 1.75kW AWPS are elucidated to investigate the behavior of the proposed configuration. The proposed topology is compared with conventional schemes in terms of efficiency, THD and PF. Test results are conferred to corroborate the efficacy of proposed SMPS for arc welding applications.