Research On Pricing Strategy And Optimal Charging Of Electric Vehicles Considering Users’ Demand Response Degree

In recent years,in order to cope with the increasingly serious environmental pollution and energy shortage,electric vehicles have achieved rapid development.However,large-scale electric vehicle may impact the load of the grid,resulting in a decline in power quality.On the other hand,the charging of electric vehicles has the characteristics of intermittent charging,thus it is possible to optimize its charging.If the charging process is reasonably optimized,electric vehicles can also participate in the process of peak shaving and frequency modulation of the power grid to increase the stability of power grid.In order to reduce the impact of disorder charging of electric vehicles on the power grid,it is necessary to cope with the loads of electric vehicle on demand side and guide users to charge coordinately.As an important part of demand side response technology,time of use(TOU)tariff can effectively guide users to change their inherent power consumption mode according to the dynamic change of power price,so as to reduce the power load and enhance the stability of system.This paper mainly studies the charging optimization strategy and pricing strategy under the TOU tariff policy.First of all,the charging and discharging characteristics of electric vehicles are modeled mathematically,and the influence of disorder charging on the stability of power grid is analyzed.Firstly,the charging and discharging modes and the power characteristics of batteries of electric vehicles are introduced.On this basis,the load model of disorder charging of electric vehicles is established.Then,Monte Carlo simulation method is utilized to simulate the load of disorder charging.The results show that the disorder charging behavior of electric vehicles will increase the load of power system,and influence the stable operation of the power system.At the same time,the higher the number of electric vehicles,the greater the impact on the stable operation of the power grid.Furthermore,the mathematical model of coordinated charging and discharging of EV under TOU policy is established.Firstly,the policy of demand response and TOU policy is introduced.On this basis,the specific time period of TOU policy is obtained by K-means algorithm.Secondly,a multi-objective model is established to minimize the user charging cost and the peak-valley difference rate of the grid load.The Pareto solution set of the problem is obtained by multi-objective genetic algorithm(NSGA-Ⅱ)and fuzzy membership method.The results show that the TOU policy is very effective to lead users to charge coordinately.At the same time,the higher the user demand response degree,the better the effect of peak shaving and valley filling.Finally,a model considering user demand response degree and social economic benefits is established,then the optimal TOU price is given and the influence of government subsidy on demand response degree is analyzed.Firstly,a quantitative model of user demand response degree based on consumer psychology is proposed.By classifying the demand response of electric vehicles,the response models of different types of electric vehicles are built.Furthermore,a TOU price model considering multiple interests is established.And the optimal value of TOU price is obtained by NSGA-Ⅱ.Finally,the value of subsidy that enables users to achieve maximum demand responsiveness is calculated.The results of TOU price provides some reference for policy makers.At the same time,to a certain extent,the government is able to attract more users to participate in the demand response by increasing the subsidies appropriately.