Active-clamping ZVS single-stage PFC converter

As the power switches of traditional PFC(Power Factor Correction) converter working in hard-switching mode has high voltage stress, combined with the techniques of phase-shifted full-bridge and active-clamping, a PFC converter based on traditional Boost circuit is proposed, which realizes the power factor correction and DC/DC conversion by single stage circuit. By the active-clamping circuit parallel to the bridge and suitable control strategy, the voltage spike induced during the commutation by the leakage inductance of transformer can be greatly absorbed and the voltage stress of power switches is reduced. Both the bridge switch and clamping switch realize the ZVS(Zero-Voltage-Switching) by making use of the resonance between the leakage inductance of transformer and the parasitic capacitance of switch. The conditions of ZVS operation are obtained by analyzing the working principle of converter. Experimental results verify that the proposed converter realizes near unity power factor, low switch voltage stress and ZVS.