Implementation and comparison of two common power factor correction techniques in AC/DC switching converters

In this paper, two prevailing techniques for active power factor correction (PFC) including critical conduction mode control (CRM) and average current mode control (ACM) are designed and applied to a single-stage AC/DC converter with flyback structure. The operation principles, control design procedure, and control system simulation are presented. Then, a comparison between two methods is carried out in terms of three categories involving compensation quality, efficiency and economic saving as well as control design requirement. The experimental results based on a laboratory 100W prototype are provided to test the practical performance of control strategies. The results evaluate the ability of each method to improve the power factor and reduce the total harmonic distortion (THD). They show that the ACM method presents a better compensation performance than the CRM method in the same condition. However, the design requirements and the converter power level are important in the selection of appropriate control method.