A single-stage fast regulator with PFC based on an asymmetrical half-bridge topology

This paper presents single-stage regulators with power-factor correction (PFC) based on an asymmetrical half-bridge topology. The proposed regulator is formed from a boost converter with two coupled inductors and an asymmetrical half-bridge converter with the synchronous switch technique, and it is controlled with pulsewidth modulation to achieve zero-voltage switching (ZVS). The boost converter is operated in discontinues conduction mode to achieve PFC. With the coupled inductors, input current ripple and power factor can be improved significantly. The proposed regulator has the features of constant-frequency operation, ZVS, and low voltage stress imposed on the active switches. Moreover, the regulator can achieve high power factor, high power density, high efficiency, low switching loss, and low component count, which makes its applications at medium-power levels feasible. Experimental results have verified the discussed features of the proposed regulator. Index Terms--Asymmetrical half-bridge converter, power-factor correction, zero-voltage switching (ZVS).