Research On Optimal Charging Policy Of New Energy Vehicles Based On Real-time Electricity Price

At the moment of rapid economic development,environmental protection has become one of the topics of people’s attention.In order to effectively control environmental damage and energy consumption,the state strongly encourages citizens to use low-carbon and green travel modes.Transportation electrification is to conform to the green development concept and provide people with a more environmentally friendly new mode of travel.As a typical representative of China’s energy-saving means of transportation,new energy vehicles have been widely recognized by the public because their power comes from unconventional vehicle fuels,and the use of advanced technologies in the power control and drive of integrated vehicles can effectively reduce the consumption of resources.Among many new energy vehicles,the most widely used is pure electric vehicles.Due to the power requirements of electric vehicles,charging car batteries has become one of the main concerns of car users.At present,in some first-tier cities,charging stations for electric vehicles have been established in public areas such as streets and residential areas,which has solved the problem of charging places.Then,the problem of charging cost is the next step that should be focused on analysis and research.In this paper,the optimal charging strategy of new energy vehicles under the condition of real-time electricity price is considered.Based on the change of real-time electricity price,under the limitation of limited charging time slot and target charging amount,a model for the optimization of charging strategy of new energy vehicles is proposed.This paper discusses how to minimize the charging cost of new energy vehicles under the limited time slot（that is limited number of charging times）and real-time changing electricity prices,so as to achieve the optimization of vehicle charging strategies and reduce the charging costs of car users.Based on the relevant theory of Markov’s decision-making process,the above model is converted into a three-dimensional system state space at the moment,real-time electricity price,car charging amount and effective charging time,and the decision on whether to charge the car in the current state is defined as the action set,and after the decision is taken,the charging cost of the car user is used as a cost function.In addition,in order to ensure that the car can complete the charging task within a limited time slot,this paper proposes a loss function that tends to be infinite,as a punishment for not completing the charging target.The above Markov problem is then solved by taking the value iteration algorithm to solve the lowest charging cost of the car.Based on the characteristics of the supermodel and submode functions,it is applied to the cyclic Bellman equation,and the proof of the mathematical induction method is used to propose two monotonic structures of the optimal charging strategy of the new energy vehicle:（1）If the final loss function increases with the increase of the amount of charging required by the target,then the optimal charging strategy of the new energy vehicle is monotonically decreasing.That is,the optimal charging strategy decreases monotonically in the remaining charging time;（2）If the final loss function is not completely consistent with the increase or decrease of the amount of charging required by the target,then the amount of charging that is still needed at the moment will increase more and more with the increase or decrease of the charging loss function,and the optimal charging strategy of the new energy vehicle will increase monotonically under the amount of charging that is still needed.The result of these two monotonicities greatly reduces the computational complexity required to implement an optimal charging strategy.Finally,through matlab numerical simulation,the strategy is quantitatively analyzed and evaluated,which further verifies the conclusion that the optimal charging strategy of new energy vehicles is monotonic in two dimensions: residual charging time slot and required charging amount.Through the analysis and study of the optimal charging strategy of new energy vehicles under the real-time change of electricity prices,new energy users can save charging costs.At the same time,for consumers who have the intention to purchase related new energy vehicles,reduce the troubles caused by charging costs,encourage more consumers to buy and use new energy vehicles,reduce environmental pollution caused by vehicle exhaust emissions,and advocate green and low-carbon travel.