Collaborative Suppression Method Based on Current Preprocessing and Active Power Decoupling for Second-Order DC Voltage Ripple in PFC Converters

This paper presents a collaborative second-order voltage ripple suppression control method for single-phase power factor correction (PFC) converters. First, the causes of second-order DC output voltage ripples are analyzed. Then a modified current preprocessing mechanism is presented for the PFC in order to elevate valley power and suppress peak power, which is able to reduce the second-order power fluctuations. Parameter design and constraints are further provided to obtain a reasonable trade-off between current distortion and the suppressing effect. Meanwhile, an active power decoupling (APD) circuit reusing a capacitor half-bridge is also embedded into the PFC converter. For the APD circuit, this paper calculates and determines the capacitor voltage reference for the purpose of absorbing second-order power fluctuations. Moreover, a closed-loop control strategy for APD is presented to achieve tracking of the capacitor voltage. A coordinate control algorithm is introduced to monitor the cooperative relationship between PFC and APD control. Finally, a 400 W PFC prototype is constructed, and experimental tests are then carried out for verification. The results obtained based on the prototype can confirm the feasibility of the control strategy and the correctness of the theoretical analysis discussed in this paper.