Study On Single Phase Active Power Factor Correction Converter With Low-ripple

With the development of the power electric technology, PFC(Power Factor Correction) has become one of the most important research aspects in power electronics field. Boost converter is usually applied as the pre-regulator of the two-stage PFC converter to get a unit power factor, because of its advantages such as smaller input current distortion, high efficiency. Boost PFC operating in Discontinuous Conduction Mode (DCM) has some advantages. Firstly, input current of this converter naturally follows the sinusoidal line voltage, the current control can be removed and the whole control loop is simplified, Moreover, Zero Current Switch is another advantage for DCM Boost PFC, it reduces power loss in the power switches and the snubber circuit which suppresses reverse recovery current of the output rectifier is not required. Although DCM Boost PFC has many advantages, it is generally used in low-power application. The main reason is large ripple of input current makes switching devices loss high.To solve this problem, this paper presents a low-ripple Boost PFC which operates in discontinuous current mode. Therefore, there is no reverse recovery current of the output rectifier. An independent inductor and a capacitor are applied in the topology so the circuit input current ripple is reduced, the output current peak is smaller, the electromagnetic interference of power or load generated by current ripple is reduced, EMI filter is saved, and unity power factor is obtained. Moreover, low- ripple structure can be used in interleaved Boost PFC circuit, so that the power level of PFC can be greatly improved, the scope of application is expanded.This paper mainly discussed following topics:(1) After a brief introduction of research background and review of the development of power factor correction technology, introduces the traditional single-phase Boost PFC, analyzes the single stage and the two stages power factor correction; introduces several PFC circuit topology; describes the characteristics of several widely used control method. The research purpose and contents are given.(2) Presents the a low-ripple Boost PFC topology, analyzes the converter operation process in Discontinuous Conduction Mode and Critical Conduction Mode, the converter's power factor ,the working conditions and switch duty cycle of CRCM are derived, further, studies the application of low-ripple structure in the interleaved PFC Converter and its working process.(3) Establishes the small signal model of low-ripple Boost PFC converter's main circuit and control circuit, by simulation software to simulate the system to verify the correctness of theoretical analysis.(4) Derives the main parameters of the main circuit and control circuit, designs the hardware circuit. Finally, the experimental results of a lower-power circuit prove the correctness of theoretical analysis and simulation.