A single-phase three-level flying-capacitor PFC rectifier without electrolytic capacitors

Abstract

A component-minimized and low-voltage-stress single-phase PFC rectifier without electrolytic capacitor is proposed in this paper. Component minimization is achieved by embedding an active pulsating-power-buffering (PPB) function within each switching period, such that typical add-on power electronic circuits for PPB is no longer needed. Additionally, with a three-level flying-capacitor configuration, the voltage stresses of switching devices can be reduced more than 50% as compared to existing solutions that are based on embedded PPB. The relationship between the inductance requirement and the patterns of the modulation carriers, and how it can be utilized to minimize the magnetics of the rectifier, is also discussed. A 110 W hardware prototype is designed and tested to demonstrate the feasibilities of the proposed rectifier. An input power factor of over 0.97, peak efficiency of 95.1%, and output voltage ripple of less than 4.3%, across a wide load range have been experimentally obtained.