Modeling of the boost power factor correction rectifier in mixed conduction mode using PWA approximation

PFC converters for higher power are commonly designed for continuous conduction mode (CCM). However, at light load, discontinuous conduction mode (DCM) will appear close to the crossover of the line voltage, causing the converter to switch between the two conduction modes. As a result, the converter dynamics change abruptly, producing input current distortion. In this article a piecewise affine approximation has been employed in modeling a boost power factor correction converter operated in the mixed conduction mode. This approach makes the new model very useful in large signal analysis of PFC rectifiers and design of controller. The results obtained from the proposed model are compared with those of linear approximation and the exact nonlinear model.