PFC bridgeless converter for welding power supply with improved power quality

This paper proposes a power factor corrected (PFC) two stage AC-DC converter suitable for arc welding applications. The proposed circuit is made up of a bridgeless (BL) zeta converter at the front end and full bridge (FB) buck converter for high-frequency isolation. The BL zeta converter eliminates the input diode bridge rectifier (DBR) thereby minimizing the conduction losses. The discontinuous current mode (DCM) operation of BL zeta converter naturally provides power factor correction at AC mains in an effective manner. The proposed converter offers several meritorious features like fast parametrical response to load and source voltage variations andinherent short-circuit current limit resulting in better welding performance and weld bead quality. The performance of the system is investigated to assess its power quality in terms of input power factor (PF), total harmonic distortion (THD) of the AC mains current, voltage regulation and robustness. The system is found to perform extremely well adhering to international power quality norms.