Research On Charge And Discharge Strategy For Electric Vehicles Based On V2G Technology

Facing the increasingly severe energy crisis and environmental problems,high-energy consumption,high-emission vehicles will be replaced by low-energy,zero-emission,low-noise electric vehicles,which has become a trend in modern society.Electric vehicles have great development potential and broad application prospects as an emerging clean,efficient and intelligent transportation vehicle.Large-scale electric vehicles connected to the grid in V2G mode has brought many challenges to the grid,including unconsidered charging requirements,insufficient inertia supports,lacking of operation stability and so on.Therefore,this paper proposes an electric vehicle V2G management and control system.On the one hand,the scheduling strategy is used to meet the charge requirements of electric vehicles,to avoid the problem of load peaks caused by a large number of electric vehicles connected to the network,and achieve peak clipping and valley filling of the power grid;On the other hand,enhancing the operation of the grid points by establishing reasonable converter control strategies could improve the stability of the grid and optimize system dynamic response.The main work is as follows:(1)This paper proposes the mechanism of electric vehicles V2G management system,introduces the characteristics of its application scenarios,and elaborates on the functions and operating principles of each layer of the architecture.The management system consists of electric vehicle charging and discharging scheduling system aimed at suppressing peak-to-valley difference and electric vehicle charging and discharging converter system aimed at providing stable and flexible interfaces.(2)Describe the electric vehicle V2G scheduling strategy in detail.Considering the current load of the regional power grid and the state of electric vehicle connected to the grid,the strategy utilizes the fuzzy control algorithm to determine the power flow between the newly connected electric vehicle and the power grid to provide auxiliary services for peak clipping and valley filling for the power grid,and make full use of electric vehicles to schedule resources with high optimize calculation speed and high operational efficiency.(3)Introduce the topology and control strategy of electric vehicle charging converters.On the AC/DC side,an adaptive control strategy of inertia damping is proposed.The angular frequency offset is introduced to form the inertia damping adaptive control based on traditional virtual synchronous machine control to realize the flexible grid connection.On the DC/DC side,a suitable charging strategy is adopted to improve the charging acceptance of the batteries and charging efficiency of the power battery.(4)The simulation is conducted to verify the correctness and effectiveness of proposed electric vehicle scheduling strategy and converter control strategy.