Investigation and Implementation of a Starting and Voltage Spike Suppression Scheme for Three-Phase Isolated Full-Bridge Boost PFC Converter

A starting and voltage spike suppression scheme is proposed and investigated in a three-phase isolated full-bridge boost power factor correction (PFC) converter with the passive flyback auxiliary circuit. In steady state, the auxiliary circuit in the PFC converter is operating as a passive clamp circuit, by which the voltage spike across primary side of the power transformer is suppressed, and the absorbed energy can be transferred to the load during one charging period by the resonance of the inductors and capacitors in the auxiliary circuit. In starting state, the output filter capacitor is charged by the flyback inductor in the auxiliary circuit, and the PFC converter can achieve normal starting-up. The operational processes of the PFC converter are analyzed in both steady and starting states. Furthermore, the design considerations of the key parameters are discussed. Finally, experimental study has been done on a laboratory-made three-phase PFC prototype, and the feasibility of the proposed scheme and the validity of the theoretical analysis are verified by the experimental results.