Research On Orderly Charging And Discharging Of Electric Vehicle Battery Swapping Cabinet

With the rise of electric vehicles(Electric Vehicle,EV).battery swapping has gradually developed into a business model.Different from charging piles,battery swapping cabinet puts the scene of battery charging on the charging bin inside cabinet.It carries out unified charging scheduling for a large number of batteries,and use fully charged batteries to meet the battery swapping demand of electric vehicle users.However,large-scale grid-connection of batteries in the cabinet will cause the problem of "peak on peak" to the power grid,which will increase the operation cost of the power grid.Meanwhile,the improper location layout of the battery swapping cabinet will also increase the operating cost and construction cost of the operator,and ultimately reduce the total revenue of the battery swapping cabinet.Therefore,it is of important research value to analyze the layout optimization strategy of battery swapping cabinet and study the orderly charging and discharging problem of battery swapping cabinet on this basis.In this paper,a two-stage layout optimization scheme for the location selection of battery swapping cabinet is proposed.Firstly,the upper level optimization model is established to select the most reasonable position of the cabinet among several candidate points,so as to maximize the profit of operator.Secondly,an appropriate distribution route is developed for the logistics company in the lower level optimization model,so that the logistics vehicles loaded with goods start from the distribution center and orderly serve all delivery destinations under certain constraints to minimize the time cost.Then the combinatorial optimization algorithm based on genetic algorithm and CPLEX solver is used to solve the model,and the layout optimization model is linearized by constructing auxiliary variables to facilitate the solution.Finally,an example analysis is carried out to verify the effectiveness of the optimal layout of the cabinet.According to the battery swapping cabinet with optimized layout,this paper establishes the orderly charging and discharging model of the cabinet.By setting different charging and discharging power of the batteries in the cabinet,the orderly charging and discharging scheduling of the battery swapping cabinet is realized.This paper focuses on the decision of four charging and discharging states(fast charging,normal charging,slow charging and discharging)of the charging bin.Firstly.Poisson probability model is used to predict EV users’battery swapping demand,and specific membership function is used to determine the number state of available batteries in the cabinet.Then the corresponding control strategy of charging and discharging is proposed according to the energy storage characteristics of battery discharging to the grid and the time-of-use price policy of the grid.Secondly,Monte Carlo algorithm is used to simulate the distribution of the number of EV users to the battery swapping cabinet and the distribution of the remaining battery power,and the orderly charging and discharging model of the battery swapping cabinet under the condition of multiple objective functions and multiple constraints is established.Thirdly,particle swarm optimization algorithm is used to solve the ordered charge and discharge model,and adaptive inertia weight is used to overcome the fixed parameters of traditional particle swarm optimization algorithm,and immune algorithm is combined to solve the problem that it is easy to fall into the local optimal solution.Finally,the effectiveness of the orderly charging and discharging model is verified by simulation.This paper designs the hardware and software system of the cabinet.First,complete the design of main program,communication process,human-computer interaction program,user identification program,output control program of the battery swapping cabinet system.Secondly,the system is divided into four parts:the main controller circuit,the communication circuit,the human-computer interaction circuit and the CAN repeater circuit.The CAN repeater circuit is designed and applied to assign different communication marks to the battery,so as to realize the function of multiple batteries charging at the same time.Thirdly,adopt the modular design concept of the structure and electrical architecture of the battery swapping cabinet block design,each module is responsible for realizing a function,the organic combination between the modules together constitute the battery swapping cabinet system.Finally,the experimental platform of charging control of the cabinet is built to realize the charging of different power of the battery by the charger.The experimental results show that the designed battery swapping system can basically achieve various expected functions.