Research of soft switching arc welding inverter power supply with high-frequency and high-power

High-frequency inverter power supply is an inevitable developing trend of modern industrial arc welding power supply. The control strategy of phase-shifted full-bridge is usually used in large-scale inverter welding power supply. However, it is characteristic with difficultly realizing ZVS for lagging bridge, low efficiency with light load and serious Electro-Magnetic Interference (EMI). In this paper, proposed controllable resonant inductance technology increase the range of soft switching operation and decrease the dependency of ZVS operation on the load current. The value of controllable resonant inductor is controlled by output current of power supply. By controlling the value of resonant inductance properly, the duty cycle loss may be reduced and the necessity of the deadzone control of the same leg is eliminated. By adopting methods such as allocate the value of blocking capacitors properly, decrease leakage inductance of high frequency transformer and eliminate the parasitic capacitance of switching tube and primary side of transform, the soft switching of low voltage large current inverter arc welding electrical source is implemented, and the efficiency and the common conducted EMI of the power supply are improved. A power supply simulation model is made based on PSIM, and a high efficient high frequency inverter arc welding power supply prototype is developed, which single output is 60V/500A, power is 30kW and switch frequency is 20kHz. Simulations and experimental results demonstrate the validity of the proposed method.