The Overall Dynamics of Power-Factor-Correction Boost Converter

The overall dynamics of power-factor-correction (PFC) boost converter, including the fast-scale instability, the low-frequency stable periodic operation, the low-frequency bifurcation and chaos, are investigated by using the combined continuous conduction mode (CCM) and discontinuous conduction mode (DCM) model. It is conventionally assumed that the converter operates in CCM in the design and analysis process of a PFC boost converter, which prevents us to understand the overall dynamics of the converter. It has been pointed out that the DCM can occur in the PFC boost converter, especially, in the light load condition. Therefore, the DCM model has to be included to analyze this PFC converter to cover the possible DCM operation. The unified model for describing the overall dynamics of the PFC boost converter is derived, which can be used to analyze the overall dynamics uniformly. By using the proposed combined model, the fast-scale instability can be detected. At the same time, the low-frequency bifurcation diagram is derived by proposed model, which makes the route from period-double bifurcation to chaos clear. The overall dynamics derived from the proposed method is verified by the experimental results