Dynamics analysis of a low-voltage stress single-stage high-power factor correction ac/dc flyback converter

In this study, by integrating a power factor correction buck-boost cell with a dc/dc flyback cell and adding an auxiliary transformer for energy-divider approach, a single-stage high-power factor correction (HPFC) ac/dc flyback converter with low-voltage stress is proposed. The proposed converter exhibits the capabilities of high-power factor and low-voltage stress across the bulk capacitor when its dc/dc cell operates in continuous conduction mode. In this study, the operating principle is presented. The small-signal model of the proposed converter is also derived herein. It shows that the proposed converter with an auxiliary transformer exhibits better dynamical behaviour than the single-stage HPFC ac/dc flyback converter without an auxiliary transformer. Moreover, a proportional-integral controller is well designed for output voltage regulation. Finally, the accuracy of theoretical analysis and performances of overall system are thereby validated by experimental results.