Three-Phase Isolated High-Power-Factor Rectifier Using Soft-Switched Two-Switch Forward Converter

A three-phase, high-power-factor (HPF), soft-switched isolated rectifier is introduced. The proposed circuit employs a discontinuous-voltage-mode (DVM) resonant input rectifier followed by a two-switch forward converter. In addition to achieving HPF rectification, the circuit also offers soft switching of the forward converter switches. The operation and performance of the proposed topology were verified on a 3-kW prototype operating from a three-phase line-to-line voltage of 220 V ? 10%. The experimental results show that the input-current-shaping using the proposed rectifier can be performed with a THD less than 6% over the entire line range and in the load range from full load down to less than 10% of full load. The measured efficiency of the experimental prototype at full load and nominal line was approximately 90%.