Development of the active capacitor for PFC converters

In this paper, the active capacitor is proposed to replace the electrolytic capacitor of the power factor correction (PFC) converter. Conventionally, a bulky electrolytic capacitor is connected in parallel with the output stage of the PFC converter to reduce the output ripple voltage. However, the electrolytic capacitor would shorten the lifetime and reduce the reliability of the PFC converter. Thus, the active capacitor is proposed to reduce the required capacitance of the PFC converter so that the electrolytic capacitor can be replaced by the film capacitor. The mathematical analysis and component selection of the active capacitor are presented in this paper. Simulation and experimental results of a 200W prototype PFC converter are presented to verify the performance of the proposed active capacitor.