Research On Soft Switching Technology Of Three-phase VIENNA Rectifier

The three-phase VIENNA rectifier has the advantages of low harmonics,unit power factor,low switching stress and no arm through risk.However,the basic PFC structure of three-phase VIENNA rectifier circuit is Boost unit,which has some problems such as reverse recovery of booster diode,high switching loss,high electromagnetic interference and low power transmission efficiency,which limits the performance improvement of rectifier.Therefore,this paper studies the soft switching technology of three-phase VIENNA rectifier in order to reduce its electromagnetic interference and improve its power transmission efficiency.The main work contents of this paper are as follows:This paper describes the development status of single-phase PFC and three-phase PFC soft switching technology,and points out the importance of three-phase VIENNA rectifier soft switching technology,and then puts forward the research purpose and significance of this paper.Then the working principle of three-phase VIENNA rectifier is discussed,and the power loss is calculated in a simplified manner..For the research of the new soft switching topology,starting from the three-phase VIENNA rectifier topology,based on the basic idea of Boost circuit soft switching technology,two new three-phase VIENNA soft-switching topologies are proposed by this paper,which are the minimum voltage active clamp three-phase VIENNA circuit and shunt three-phase VIENNA soft switching circuit.Both new topologies can solve the reverse recovery problem of the boost diode.The former achieves zero-voltage turn-on and zero-voltage turn-off of switching devices in the full range,and has excellent characteristics of low voltage stress,while the latter achieves zero-current turn-on and zero-voltage turn-off of switching devices in the full range,and has excellent characteristics of simple structure and high efficiency.In order to study the feasibility of the proposed topologies,the basic working principle,soft switching conditions and device stress of the two new topologies are analyzed in detail,and the simplified calculation scheme of power loss and the design method of circuit parameters are given.Based on the designed circuit parameters,this paper completes the simulation verification of two new soft switching topologies,and builds the experimental platform of traditional three-phase VIENNA circuit and two new three-phase VIENNA soft switching circuits.The experimental results verify the correctness of the studied topologies.Based on the experimental data and theoretical loss calculation,this paper draws the loss curves and efficiency curves of the traditional three-phase VIENNA circuit and two new three-phase VIENNA soft switching circuits.Through the comparative analysis of the three topologies,the validity of the studied topology is verified.