A single-stage asymmetrical half-bridge AC/DC converter with coupled inductors

This paper proposes a single-stage high-power-factor asymmetrical half-bridge AC-DC converter for power factor correction. The proposed converter is developed by integrating an asymmetrical half-bridge DC-DC converter with a set of coupled inductors and a blocking diode to achieve the single-stage AC-DC conversion with the buck-boost type power factor correction. By using the coupled inductors, the proposed converter can achieve near unity power factor and low total harmonic distortion without using extra switches and control circuits. Thus, the overall efficiency and power density of the AC-DC converter can be improved. The component counts and product cost can also be reduced. Moreover, the proposed converter can achieve zero-voltage switching for both power switches, so the switching loss can be reduced. Hence, the proposed converter has the advantages of near unity PF, low THD, zero-voltage switching, low product cost, and little component counts. A 100W experimental prototype circuit was built to verify the effectiveness of the proposed converter and the experimental results are presented in this paper. The proposed converter achieves a near unity power factor of 0.99 and low THD of 4.95% at 110Vrms line voltage.