New formulation for stability analysis of power factor correction converters

New regulations and future standards highlight power factor correction (PFC) as a basic requirement for switching power supplies. One of the most essential problems is the stability characteristic of a PFC circuit. Detection of a new instability phenomenon in the stable region predicted by the prior linear PFC models makes us more suspicious to these linear models, and reveals the lack of considerations on the nonlinear models. This forces us to investigate these problems and to develop new approaches. This paper has developed an exact nonlinear model performing the real operation of a boost PFC converter. This nonlinear model detects this instability phenomenon. Then a simplified and accurate nonlinear model is developed and verified experimentally. This model is needed for the design and analysis of the stability for PFC converters. An instability map is introduced to determine the boundary between stable and unstable operation ranges.