Charge And Discharge Control Method Of Electric Vehicle Based On Fuzzy Logic

With the large number of electric vehicles connected to the grid,the stability of the power grid will face a serious threat.We need find a way to appropriately coordinate electric vehicle charge and discharge,at the same time,with the extensive use of electric vehicles and electric vehicle charging station large-scale construction,people began to think about the development of electric vehicles and charging stations of the new features.That is Vehicle to Grid conception.Electric vehicle energy storage battery can be seen as a distributed energy storage unit,in addition to draw energy from the grid for driving,it can also feedback the battery energy to the grid.A reasonable control of the electric vehicle charge and discharge time and power can adjust the grid peak and valley difference,to flat load profile and improve the operation efficiency of the grid.This paper introduces the concept of V2 G at first.According to the characteristics of small capacity and large dispersibility of electric vehicle,this paper introduces the use of hierarchical partition control mode to establish an electric vehicle control center as a tripartite agency of the power grid dispatching center and electric vehicle users.The electric vehicle control center coordinate communication between the grid dispatching center and electric vehicle users,collecting electric vehicle information,issuing instruction of dispatch center control.Then,the paper introduces the principle of the electric vehicle charging and discharging system to support the power grid and the related V2 G system model,including the distribution system model of the electric vehicle charging station,the specification of the battery model,the overall structure design of the V2 G charging station and the energy conversion unit of the system The V2 G charging station consists of a power calculation unit,a V2 G fuzzy controller and a power conversion unit.The power conversion unit uses a constant power control mode to track the power control signal output by the V2 G fuzzy controller.In this paper,we focus on the charging and discharging control strategy of electric vehicle based on fuzzy logic control.The V2 G fuzzy controller uses the current voltage of the current grid and the total energy of the electric vehicle in the charging station as the input and control the power of the V2 G inverter as the output,controlling the power flow between the electric vehicle and the power grid.The power flow between the electric vehicle and the power grid is controlled by selecting the appropriate fuzzy method,the fuzzy control rule,the reasoning method and the solution of fuzzy rule.In order to verify the performance of the control strategy,four simulation scenarios were set up for the electric vehicle charging and discharging.The simulation results were analyzed by Matlab/Simulink.The simulation results show that the proposed control strategy can effectively control the charging and discharging power of electric vehicles at different times to achieve the peak load shaving and filling the valley,verifying the effectiveness and feasibility of the control strategy.