An improved current compensation method for high PF and low THD in digital boost power factor corrector

Abstract

Continuous conduction mode (CCM) boost power factor corrector (PFC) is widely used for high power applications such as server power supply. PFC performs AC/DC conversion with nearly unity power factor (PF) and low current harmonic distortion. However, the electromagnetic interference filter capacitors in front of the bridge diode and input filter capacitor behind the bridge diode incur phase leading of input current. This phenomenon reduces PF. In this paper, an improved digital compensation method for phase leading of input current in CCM boost PFC is proposed. By using this method, the power system can achieve high PF and low total harmonic distortion. Moreover, it is very simple to implement and has short computation time in digital controller. The principle and analysis of the proposed method are presented. The performance and feasibility are verified by experimental results from the high line, i.e. 230vrms input, 750W/400V output prototype.