Research On Control Strategy Of Electric Vehicle Participating In Grid Frequency Regulation

Fossil energy is not renewable,and the development of electric vehicle(EV)will become the mainstream.As a new type of controllable load,EV has many opportunities and challenges when it is connected to the smart grid on a large scale.On the one hand,when a large number of electric vehicles are connected to the power grid through charging station,it will lead to the loss of damping and inertia of the power system.On the other hand,electric vehicles are stationary in most time of a day,and its on-board batteries store enormous amounts of energy that can be utilized.In this paper,the control strategy of electric vehicle access to power grid based on virtual synchronous machine(VSM)is adopted,it is necessary to study its charge and discharge control and the scaled electric vehicle’s auxiliary frequency modulation strategy for the power grid.An AC and DC side control strategy based on VSM for two-way charging and discharging is presented.Damping and inertia are added to the charger to adapt to the change of power grid.This strategy can control the power change and charging and discharging conversion of the EV,and participate in the inertia response of the frequency change of the power grid,enable the electric vehicle load to provide active power support for the grid.The primary frequency regulation function of EVs participating in power grid frequency regulation is analyzed.A fuzzy control-based adaptive droop coefficient control strategy for EVs participating in the primary frequency regulation of the power grid is proposed,which achieves better frequency regulation control effect.This strategy maintains the charging status of EV batteries,also can better meet the travel needs of users,and avoid the impact of excessive charging and discharging on EV batteries.In view of the randomness of EV travel,Monte Carlo method is proposed to simulate the random behavior of large-scale EVs.A dynamic model of virtual energy storage power station is built by clustering EVs.And the working mode of the virtual energy storage power station participating in automatic generation control(AGC)of power grid is analyzed.An AGC control strategy based on Model Predict Control(MPC)method is presented.The established virtual energy storage power station model and its control method can effectively enable the controllable energy in largescale EVs to participate in the frequency modulation function.The AGC control strategy using the MPC method can effectively weaken frequency fluctuations and obtain better frequency modulation effects.The simulation results verify the feasibility and validity of the proposed strategy.