Research On Decentralized Optimization Scheduling Of Electric Vehicle Charging Station And The Design Of Simulation Platform

Due to the serious shortage of global energy reserves,there is a serious shortage of non-renewable energy such as oil.At the same time,the greenhouse effect has also been increasing year by year.Obviously,traditional fuel vehicles have not met the requirements of future development.It is imminent for the car to seek a motive energy alternative to fuel,so electric vehicles emerge as the times require,and they are vigorously promoted and developed by all countries.Due to electric vehicles have advantages such as no emissions,only consumes electricity and so on,it is trend that a large number of electric vehicles will be popularize.However,the security and economic operation of the power system is impacted or even challenged by the disordered charging of large-scale electric vehicles,especially for the distribution system.Aiming at the defects of centralized optimization and control method and the fixed pricing strategy,a decentralized optimization strategy of ordered charge scheduling is proposedbased on the Lagrange relaxation method.The traditional centralized charging optimization problem of electric vehicle charging station is decomposed into N sub problems(N is the number of electric vehicles demanding charging).The maximum profits of the charging station are used as the objective function in the optimization model.The constraints of power demand of users,charging time,capacity of transformer and time-of-use(TOU)price of charging station are taken into consideration.In order to verify the effectiveness of the proposed method,Monte Carlo method is adopted to simulate the charging demand of electric vehicles.The profits of charging station,the effect of clipping load peak and the calculation efficiency under the fixed price and TOU price strategy of the charging station in situations of ordered charging and disordered charging when adopting centralized and decentralized optimization respectively are simulated and analyzed.The simulation results show that the proposed method can significantly increase the profits compared to use thedisordered charging and fixed price strategy.By contrastwith the centralized optimization,the computational efficiency of the proposed decentralized optimization is much higher.Though the charging station using TOU price has the effect of filling valley,the effect is not tooideal in stabilizingthe load fluctuation.Meanwhile,an optimization scheduling simulation system for electric vehicle charging station based on CPLEX and MATLAB is established for the optimization of electric vehicle charging period.In this paper,we use three approaches,namely,disorder charging,centralized control charging and decentralized control charging,and comparetheir influence on local daily load curve.Then,this paper establishes the interface of the simulation system by using the graphical user interface design function(GUI)in MATLAB,and then sets the properties of each control and compiles the M file to realize the optimization control function,and through compiling it finally forms an operational file.The simulation system has the advantages of visibility,versatility and controllability,which can help to complete the optimal scheduling simulation experiments of electric vehicle charging optimization in charging station.