A new quasi-single-stage isolated three-phase ZVZCS buck PWM rectifier

A new quasi-single-stage isolated three-phase zero-voltage/zero-current-switched (ZVZCS) buck PWM rectifier for high-power off-line applications is proposed. It consists of a three-phase buck bridge switching under zero-current and a phase-shift-controlled full-bridge with ZVZCS, while no intermediate DC-link is involved. Input power and displacement factor control, input current shaping, tight output voltage regulation, high-frequency transformer isolation, and soft-switching for all the power devices are realized in a unified single stage. A 6 kW, 50 kHz prototype for telecommunication applications has been developed and preliminary tests for the prototype validates the operation of the proposed rectifier. Simple control, high efficiency and fast dynamics are among its salient features.