Three-phase switchmode direct conversion type welding power supplies with active power factor correction

A topology of inverter-type power supply with three-phase input and transformer-isolated output is presented. The power supply is built using the technique of direct conversion of three-phase mains voltage to high-frequency voltage. Applying the principle of direct conversion allows reducing the number of elements in the inverter power path, thus increasing its efficiency. In addition, by using an appro-priate control algorithm, it is possible to maintain close to unity input power factor