HF Transformer Linked Soft Switching PWM Full-Bridge DC-DC Power Converter for Portable Arc Welding Machine for Grid and PV Applications

This paper presents a circuit topology for portable Shielded Metal Welding Machine (SMAW) integrated by soft-switching PWM full-bridge dc-dc power converter that can work with both utility grid 220Vac or solar DC 300Vdc as the input source. The power circuit maintains zero voltage switching (ZVS) to reduce switching losses. This technique leads the circuit to operate at a high switching frequency of 20 kHz. High switching frequency with the softer Pulse width modulation (PWM) converter, the better will be the performance with high-frequency (HF) transformer and passive components. Thus, the power density and operational efficiency will be higher compared to a typical hard switching converter. Considering ac input from the utility grid, a boost converter has integrated to improve power factor (PF) and lower THD. A 1 kW prototype is designed and developed that consists of a rectifier, boost converter, full-bridge inverter, HF ferrite core transformer, LC filter, and welding accessories (clamp, electrode, etc.). The effectiveness is tested under low voltage (LV) and high current (HC) situation as an arc welding machine by using both grid and photovoltaic (PV) array.