Research On The Optimal Control Strategy Of Electric Vehicle Participating In Grid Auxiliary Services

The number of fuel vehicles has been increasing significantly in the world,which has led to petroleum resources consumption and environment pollution.Electric vehicles(EV)have the advantages of zero emissions and high energy efficiency,which have developed rapidly in recent years.Relevant research has shown that the explosively blooming charging load has many negative impacts on the power grid,when a large number of electric vehicles are connected.Orderly charging can reduce load peaks and minimize the adverse effects of out-of-order charging effectively.The orderly charging of distributed EVs and their participation in gridassisted services are discussed in this dissertation.The main contents are as follows:(1)Taking the EV-connected smart distribution grid as an background,the energy flow and information interaction among EV,power supply,distribution systems and regional power grids are analyzed.The effects of EV battery characteristics,user’s driving habits and the scale of EV on the charging load of the EV are discussed.Monte Carlo simulation method is utilized to calculate the charging load,which serves as a basis for subsequent research.(2)An orderly charging method for distributed EV is proposed.A part of EVs are postponed to be charged by the controllers according to preset rules.Therefore,the goal of “clipping and filling valleys” can be realized without centralized regulation.The excessive postponement charging pile can also be avoided.Simulation results show that the proposed method can smooth the charging load curve and reduce the adverse effects of disorderly charging.(3)A power grid congestion elimination method is proposed the means of decentralized control of EV.An optimization model is established,in which preset parameters in different periods are used as control means and the load peak is to be minimized.The constraint conditions include the total load does not exceed and the capacity of the transmission network.is that the total power in the area does not exceed the capacity of the transmission grid.Grey Wolf Optimization(GWO)algorithm was introduced to optimize the preset parameters in each period.Simulation results show that the optimized parameters can further eliminate transmission grid congestion.(4)The energy efficiency control system of Qingdao Special New Energy Co.,Ltd.is studied as a case.Based on the research of system structure and charge-discharge control strategy,different working conditions under the regulation of the energy efficiency management system are analyzed.