An Isolated Soft-Switched High-Power-Factor Rectifier Based on the Asymmetrical Half-Bridge Flyback Converter

This paper presents the analysis and design of a high-power-factor rectifier that integrates a DCM operated Boost input cell with an Asymmetrical Half-Bridge Flyback converter (AHBFC). The particular connection of the DC-DC stage with the boost cell makes the DC link voltage decrease at light load, thus naturally limiting the switches' voltage stress. A suitable design procedure is described that accounts for the resonant nature of the AHBFC, and allows to calculate all converter parameters to meet the design specifications and to achieve Zero-voltage turn-on for the switches in any operating condition, considering both input voltage and load variations. The theoretical analysis is validated by experimental results taken on a 160 W rated prototype, working at the nominal switching frequency fsw = 400 kHz, with a line voltage RMS value ranging from 85 V to 135 V.