Soft-switching type 3-phase AC input rectifier with high power-factor

The authors have developed a rectifier of 5 kW output which consists of two converters, a 3-phase bridge boost-chopper to operate by zero-voltage switching (ZVS) and a full-bridge converter to operate by ZVS. As the main switches, MOSFETs are adopted for the 3-phase boost-chopper and bipolar-mode static induction transistors (B-SITs) for the full-bridge converter, thus simplifying the circuits and improving the efficiency. The rectifier developed achieved the following. The efficiency is about 93% and the power factor minimum 0.99 at the rating, and the input harmonic currents satisfy the Standard Class A of IEC (International Electrotechnical Commission). The radiated noise satisfies the CISPR22 Standard Class A.