ABSTRACT
This project reveals Parasitic-induced Current Distortion (PCD) effect in DCM boost Power Factor Correction (PFC) converter. With consideration of parasitic, accurate inductor current is derived through total differential functions of line voltage, output voltage and duty cycle. Furthermore, the proposed current model is used to analyze PFC converter under conventional Sensor less Average Current Mode (SACM) control, which is achieved by a variable duty cycle. It is found that parasitic have considerable influence to the input current, and PCD leads to a degraded power factor. In order to solve this issue, a current reshaping strategy is proposed to reduce the PCD phenomenon. Based on the damped current equations, a compensation gain is derived to reshape the input current, which reduces the current damping and distortion caused by parasitic. Both the PCD phenomenon and the current reshaping strategy are verified by simulations and experiments.