Study On Optimal Scheme For Harmonic Analysis And Management Of Ev Charging Station

With the continuous upgrading of power technology,industry and agriculture as well as various industries have increasingly strict requirements on power quality,such as semiconductor production and precision machining of nc machine tools.The high power charging machine is used to charge the electric vehicle rapidly by using the cross-direct transformation of modern power electronics technology.When a new energy vehicle is rapidly charged,the harmonic current will flow into the power grid,causing great harm to the urban power grid.Therefore,the electric vehicle harmonic management is imperative.At first,the paper introduces the topological structure of three common electric vehicle charging machines,and analyzes the advantages and disadvantages of different types of electric vehicle charging machines.Second,focuses on analyzing the application of the most widely three-phase full bridge controlled rectifier charger,using MATLAB simulation software to build a complete three-phase full bridge controlled rectifier charger not simulation model,the simulation analysis and the theory of detailed analysis of its distribution regularity of harmonic current.Finally,in view of the three-phase full bridge controlled rectifier charger harmonic characteristic,get active filtering scheme,passive filtering scheme and three kinds of hybrid filtering harmonic governance,comprehensive comparison from three ways,filter cost and the effect of harmonic governance,found that the harmonic charging station configuration in the treatment of the hybrid filter is the most high cost performance solution.The main research contents of this paper are as follows:1)three common topological structures of ev charging machines are introduced,and a complete simulation model is established for the most commonly used three-phase full-bridge uncontrollable rectifier charging machines.In order to simulate and analyze the harmonic distribution law of ev charging station,the equivalent simplification model of ev charging station is proposed.Through comparison,it is found that the complete charging model and the simplified model have the same harmonic current distribution on the side of the system,which proves the feasibility of the equivalent model.2)the harmonic distribution law of three-phase full-bridge uncontrollable rectifier charger is theoretically analyzed.The correctness of theoretical analysis is verified in MATLAB/Simulink simulation software.At the same time,MATLAB simulation is used to obtain the variation rule of harmonics with charging power of electric vehicle charger.3)the harmonic management scheme of ev charging station is studied.Based on the cost and effect of the filtering scheme,the optimal harmonic control scheme of ev charging station is selected.Both the active filtering scheme and the mixed filtering scheme can make the side current of ev charging station reach the national standard of less than 5% harmonics of grid-connected current.However,the cost of the active filtering scheme is 2.3 times that of the mixed filtering scheme,that is,it is more suitable for ev charging stations to adopt the hybrid filtering scheme to control harmonics.