Bridgeless PFC Converter without Electrolytic Capacitor Based on Power Decoupling

Abstract

Due to fewer conduction devices in operating condition, the bridgeless power factor correction (PFC) converter is more efficient than the traditional PFC circuit. However, to achieve a low output voltage ripple on the DC side, a large electrolytic capacitor must be connected in parallel to the output end. To reduce the value of capacitance, this paper proposes a dual-boost bridgeless PFC converter with a bidirectional buck/boost power decoupling converter in the latter stage. The bidirectional converter absorbs double-line-frequency ripple, lowering the power pulsation at the output end while realizing power decoupling. The one-cycle control is adopted in bridgeless PFC converter, so that the input current can follow the input voltage to achieve power factor correction and decrease harmonic pollution. The power decoupling circuit is designed with a voltage outer loop using PI control and a current inner loop using model predictive current control, which alleviates the output voltage fluctuation caused by the reduction of the capacitance value of the filter capacitor, for the purpose of realizing non-electrolytic capacitor. Finally, the topology and control strategy involved in this paper are simulated and experimented to verify the validity and superiority of the theory.