An Optimized Single-Stage isolated Phase-Shifted Full-Bridge Based Swiss-rectifier

Swiss-rectifier (SR) is a family of high efficient AC-DC topologies. It's a combination of a three phase unfolder circuit which can convert the three-phase AC voltage into two sets of cyclically varying DC voltages and two symmetric DC-DC converters to achieve power factor correction (PFC). In order to obtain a zero voltage switching (ZVS) isolated single-stage rectifier system, two phase-shifted full-bridge topologies are applied to increase the working frequency of the magnetic elements. However, the current flows through at least four switches during the power conduction or freewheeling period. It is not conducive to improve the efficiency of full-bridge based SR. Thus, an optimized single-stage isolated phase-shifted full-bridge (PSFB) based Swiss-rectifier is proposed. Only one full bridge structure is used to reduce the conduction loss when the power is transmitting. Two voltage clamp branches are used to implement the PFC principle of the SWISS-rectifier. The principle of operation and the analytical equations for the stress in the semiconductor devices are discussed specifically. The performances of the proposed converter are verified by the experiments on a 10-kW 380Vac input/400Vdc output prototype with 90kHz switching frequency.