Charge And Discharge Control Strategy Of Electric Vehicle For Collaborative Photovoltaic Power Generation

With the increasing installed capacity of photovoltaic and other new energy,it has become the general trend to build a new power system with new energy as the main body.In view of the intermittenity and instability of new energy power generation,the traditional peak regulation and frequency regulation based on the generation side can no longer meet the needs of the development of new power systems.Therefore,it is of great prospect and significance to enable more flexible power sources to participate in the peak regulation and frequency regulation of the grid through the load side.Therefore,the electric Vehicle based on V2G(Vehicle To Grid,V2G)technology gives experts and scholars from all walks of life the hope and approach to solve the intermittent new energy output instability.In this paper,optical storage power generation and V2 G technology based EV charging and discharging system are studied.Taking Micro Grid(MG)as an example,the upper layer scheduling model and the bottom layer inverter control strategy are constructed to enable EV to cooperate with PV power output.In the process of constructing the scheduling model,the driving characteristics of EV users are analyzed and studied first.Then,based on the characteristics,the mathematical modeling is carried out with the minimum load difference of micro-grid system and EV charging cost as the objective function.In the solving process,after the multiple objective functions are uniformed,The improved Grey Wolf Optimization(GWO)algorithm was used to solve the load curve after EV participated in the optimization of microgrid.In the process of building the control model of the bottom inverter,firstly,the mathematical models of the optical storage power generation and the off-grid inverters of electric vehicles are analyzed and established.Then,the control strategies of the optical storage and the bottom offgrid inverters of electric vehicles are established based on the mathematical models of the two systems.Based on the actual demand of the energy interaction between electric vehicles and the power grid,The Virtual Synchronous Generator(VSG)control strategy is introduced to make it have inertia in the process of two-way energy flow.Then based on the requirements of charging and discharging power control precision and the harmonic pollution caused by largescale electric vehicles entering the network,an improved virtual synchronous generator control strategy is proposed.The Sliding Mode Control(SMC)is introduced into the virtual synchronous electromechanical double-loop voltage and current control to improve the precision of the three-phase inverter’s output power and reduce harmonics.Finally,based on the actual demand of EV collaborative PV generation,it was proposed to better coordinate PV output by constructing multiple charging station parallel system(expanded capacity).Then,Virtual Impedance Control was introduced to address the uneven power distribution caused by VSG multi-machine parallel power coupling and circulation.VIC),and through Model Prediction Control(MPC),the energy management system of bottom inverter based on the collaborative output of photovoltaic power and each charging station was constructed.To sum up,in order to verify the effectiveness and rationality of the proposed control strategy,simulation verification was carried out respectively in the Matlab2018b/simulink environment,which proved the rationality and effectiveness of the proposed control strategy.