Research On Harmonic Control Of High-power Charging Station Based On MPR

In recent years,with the development of social economy,the environmental pollution problem is becoming more and more serious.Electric vehicles have been promoted by the government with their advantages of no pollution and zero emission.The negative influence of harmonics generated by nonlinear elements in the charging process of EVS on automobiles and power grids has become an important factor hindering the popularization of EVS.The harmonic of the charging station is caused by some nonlinear elements in the rectifying process.So this topic in rectifying element of charging station is studied,the design of multiple pulse wave Rectifier circuit(Multi-pulse Rectifier,MPR for short)used in the charger,solve the problem in previous management stations harmonic when device circuit caused by the complex,high cost and difficulty of control method to increase the problem,it has been verified by simulation and experiment,harmonic control effect is obvious,the input current THD value reduced to 1.46%.The phase shift transformer in the rectifying circuit is designed as a zigzag autotransformer,and the transformer ratio is determined by the winding structure and voltage vector of the transformer,so as to increase the power density and reduce the rectifying circuit volume.Firstly,this paper describes the harmonic current characteristics of the charger and the working principle of the common 12-pulse rectifying circuit,and according to the problems,the dc link is selected to add the Boost converter to eliminate the content of high harmonics.Secondly,the structure of the charging station and the structure of the charger in the charging station are analyzed,the harmonic current of the charger is estimated by using the method of probability statistics,and the characteristics of the power output of the charging station are analyzed,so as to establish an equivalent model of the charging station.Thirdly,according to the harmonic characteristics of the charging station and the characteristics of the rectifying circuit,the influence of the inductive current on the input side of the dc side is analyzed by means of backward pushing.Finally,Matlab/Simulink platform was used to establish a simulation model for harmonic control in charging station.According to the selection and design of hardware circuit,the hardware circuit board and control circuit board were built.Through the analysis of simulation results and experimental results,the THD value was reduced to 1.46%,which verified the feasibility and effectiveness of MPR for harmonic control in charging stations.Through the analysis of the final results,the feasibility and effectiveness of MPR for harmonic control in charging station are verified,and its dynamic performance is stable.According to the different types of power batteries connected to the charger,MPR can significantly reduce the harmonic content in a variety of cases resulting in load changes.Moreover,when the output voltage is different,it can also suppress the harmonic on the ac side,and the THD value of the input current is significantly reduced.