| Electric vehicles(EVs)are cleaner and more efficient than traditional fuel vehicles,so they are strongly supported and promoted,and the trend of further replacing fuel vehicles is becoming more and more obvious.However,the access of large-scale electric vehicles will not only affect the safe operation of distribution network,but also bring new challenges to the smoothness of traffic network.Reasonable planning of charging facilities and scientific guidance of users’ charging behavior can effectively alleviate the pressure of distribution network and road network,and improve users’ charging experience.Because electric vehicles have the characteristics of traffic movement and charging load at the same time,with the continuous development of digitization,sharing,networking and electrification,the driving and charging of large-scale electric vehicles will have an interactive impact on the distribution network system and road network transportation system,and the coupling relationship between energy and information between the three is becoming closer and closer.Based on this,this paper takes the electric vehicle under the background of "vehicle-road-grid" coupling as the research object,and studies from three aspects: fast charging demand prediction,fast charging station location planning and charging guidance strategy.Firstly,this paper studies the fast charging demand forecasting method based on the coupling of urban "vehicle-road-grid".By analyzing the interaction between user driving and charging characteristics and urban traffic network and distribution network,real-time network model,distribution network model and single electric vehicle model are established respectively.Combined with multi-layer complex network theory,the interactive architecture of "vehicle-road-grid" is modeled.In view of the complexity of the changes of various driving states such as electric vehicle driving,charging and road changing under the background of real-time interaction,this paper constructs an electric vehicle space-time transfer model based on dynamic traffic flow,and then uses the idea of piecewise approximation to solve the vehicle location,electric quantity and road traffic flow according to the fixed simulation step,which can update the traffic flow in real time according to the changes of vehicle state,and recommend the optimal path for users at the same time,so as to accurately simulate the driving behavior and charging behavior of users.On this basis,the main parameters of "vehicle-road-grid" are preset,and the temporal and spatial distribution of fast charging load in the study area is simulated by Monte Carlo sampling.The qualitative analysis is carried out through the example results to verify the feasibility and rationality of the proposed prediction method.Secondly,the layout planning model of charging station based on dynamic traffic flow distribution of road network is established.Firstly,the concept of stochastic user equilibrium model is described,and its applicability to the layout optimization of charging stations is proved by formula derivation.Taking into account the factors such as travel time,charging cost and queuing time,the corresponding path impedance sensing models are designed for fuel vehicle and electric vehicle users respectively.Then,combining the layout of charging stations with dynamic traffic flow distribution,a bi-level programming model is proposed,in which the upper optimization takes the overall traffic efficiency of the road network as the goal and considers the constraints such as construction cost,safe operation of power grid and charging demand,and transmits the optimized layout optimization scheme of charging stations to the lower level;The lower level model takes the individual optimization of travelers as the goal,uses the stochastic dynamic user equilibrium model to allocate the traffic flow,and brings the allocation results into the upper level model.Finally,through alternating iteration,the optimization scheme of location and volume of fast charging stations under different proportions of electric vehicles in the road network is obtained,and the distribution characteristics and laws of traffic flow when fuel vehicles and electric vehicles are mixed at the same time are discussed.Finally,the charging path guidance strategy under the multi-party information interaction of "vehicle-road-grid" is proposed.Taking the intelligent charging guidance system as the core,combined with the intelligent transportation system and the charging station information service system,the user charging information interaction model is established.Considering the influence of information interaction on charging distribution,a two-tier queue model of charging station based on simulated clock advance is established,and a charging price negotiation mechanism between users and charging station operators and between operators is proposed.In order to give users enough benefit drive to follow the optimal path,a user decision model aiming at charging cost and time cost and meeting charging demand and queuing tolerance is constructed.Finally,based on the layout planning of charging stations,a certain scale of electric vehicles are simulated according to different negotiation participation to verify that the proposed charging navigation strategy can realize the win-win of users,charging station operators and social environment. |
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