The Influence And Improveing Strategy Research Of Electric Vehicle Charging Stations On The Power Grid

The rapidly increasing electric cars has connected more and more electric vehicle charging stations to the electricity grid.As a nonlinear load,the electric vehicle charger will produce a great deal of irregular harmonic and affect the quality of grid electricity in the charging process.Uncertainty of electric vehicle charging behavior would bring greater uncertainty to the control and management of power grid when electric vehicles is connecting to the grid.It will cause the improvement of power in some periods of time;if the charge and discharge behavior is controlled improperly,which will certainly cause negative effects at the peak load period.This paper used MATLAB/simulink software to build simulation model of the electric vehicle charger,and used the powerful module's FFT to analyze harmonic's characteristics and properties of the charger injecting the ac power grid.On the basis of single charger,a set of modules are created to simplify simulation interface,build the simulation model of electric vehicle charging station that contains different sets of chargers and study the impact of electric vehicle charging station that contains different sets of chargers on harmonic current produced by power grid.LC passive filter was used to conduct filter processing for three-phase bridge uncontrolled rectifier device charger,and a double three-phase bridge 12 pulse rectifier device was used to improve the charger,so as to reduce the impact of the electric vehicle charging stations on power grid.To sum up,the large electric vehicle fast charging stations prefer the double three-phase bridge 12 pulse rectifier device charger,while the small charging stations prefer three-phase bridge uncontrolled rectifier device chargers.According to the uncertainty of electric vehicle charging,this paper also used time of daily mileage and normal distribution formula of mileage to make a simulation to get the grid load modeling of the large-scale electric vehicle charging,and to carry out a classification on the basis of different schemes of the electric car to electricity price,to respectively simulate the response model of electric vehicle charging,discharge behavior to TOU.Then according to the data of the model,the load curve of TOU price was concluded.After using the TOU price,load curve was improved,namely,daily maximum load was improved and peak valley difference was narrowed.