Dynamics analysis of a single-stage isolated high power factor converter with a magnetic switch

The dynamics analysis of a single-stage isolated high power factor correction (PFC) converter is presented. In the single-stage PFC converter, the boost converter is operating in discontinuous conduction mode to exhibit an inherent gift of high power factor. It is integrated with a flyback converter that is operating in continuous conduction mode to achieve tight output voltage regulation. In addition, a magnetic switch is added to effectively reduce the high stress voltage across the bulk capacitor. Based on the averaging method, a nonlinear state-variable description of the converter is established. The small-signal model linearised around the operating point is then derived. The average power balance method, IsSpice simulation and experimental results successfully verify the dynamics and performances of the converter.