Design of a welding power supply with wide input voltage range

This paper proposes a power supply for welding that can adapt to a wide range of input voltages. The phase-shifted full-bridge (PSFB) converter, which is widely used as a welding power supply, is not suitable for applications where there is a wide input voltage range because of an increase in the circulating current and high-voltage stresses on the switch devices when a high input voltage is applied. To address this issue, a method to change the structure based on the input voltage is proposed by dividing the primary-side high-frequency inverter stage of the PSFB converter into two and adding path switches that can be configured in series or in parallel. The proposed circuit can lower the switch devices withstand voltage through structural changes and operate in a duty ratio with narrow fluctuations on the wide input voltage, which helps to improve the overall efficiency. The validity of the proposed method was verified through a comparison with existing topologies on a 6.6 kW prototype.