Research On Critical Continuous Mode High Efficiency Bridgeless PFC Rectifier

With more and more power electronic equipment connected to the power grid,the influence of harmonics caused by power electronic equipment is getting bigger and bigger.Relevant international and national associations have formulated a series of harmonic standards.Therefore,there was the rapid development of power factor correction technology.With the pursuit of high efficiency and power density,bridgeless power factor correction technology has gradually become a research hotspot.This paper introduces the existing bridgeless PFC circuit topology briefly,and analyzes its own characteristics.The advantages and disadvantages of the circuit operating under different states of the inductor current(CCM for Constant Continuous Mode,CRM for Critical Continuous Mode,DCM for Distant Continuous Mode)are analyzed.Current Critical Continuous Mode(CRM)enables zero-current turn-off and soft switching through resonance.Taking bidirectional bridgeless PFC and totem pole bridgeless PFC as an example,a prototype is made to verify the analysis in this paper.Which f this paper proposed a simple and feasible inductor current detection circuit or the bidirectional switch-mode bridgeless PFC to ensure that bidirectional switch-type PFC can work properly in the CRM.This article does a detailed loss analysis and algorithm design for bidirectional switched bridgeless PFC.Finally,the feasibility of the proposed scheme is verified by simulation and experiment.When compared to bidirectional switch bridge-free PFC circuit,totem pole bridgeless PFC circuit doesn't need two fast diodes,and the structure is more simple.Aiming at the totem pole bridgeless PFC,a simple and feasible inductor current detection circuit is proposed to ensure that the totem pole bridgeless PFC can work normally in the CRM.In this paper,we also do some research for some problems in practical experiments,such as THD optimization,input current zero-crossing distortion,etc.,and give the corresponding solutions.Finally,the feasibility of the proposed scheme is verified by simulation and experiment.Since the inductor current ripple at CRM is too large,using two phase interleaved to eliminate the inductor current ripple is a good choice.In this paper,the interleaved scheme for PFC rectifier at CRM is designed.The proposed interleaved scheme using pure software approach is relatively simple and easy to implement.Finally,the feasibility of the proposed scheme is verified by simulation and experiment.