A novel single-stage high-power-factor high-efficiency ac-to-dc resonant converter

This paper proposes a novel single-stage AC-to-DC resonant converter featuring a high power factor and high efficiency. The conversion circuit is of symmetrical topology which is obtained from the integration of a diode-bridge rectifier, a boost-type power factor corrector (PFC) and a half-bridge resonant converter. Two diodes of the diode-bridge rectifier are replaced by active power switches shared by the PFC and the resonant converter. By appropriately controlling the frequency of the active switches, a unity power factor and a well regulated output voltage could be achieved. The tactful circuit ensures high circuit efficiency owing to the advantages of less conducting losses and zero-voltage switching (ZVS) operation of the active power switches. A prototype circuit designed for a 100 W DC output was built and tested to verify the analytical predictions. Satisfactory results are obtained experimentally.