Research On Parameter Matching And Optimization Of Transmission System Of Pure Electric Vehicle

As the representative of new energy vehicle,pure electric vehicle is an important breakthrough to realize energy saving and environmental protection.However,before the battery technology is solved,the problems of charging and range have always restricted the development of electric vehicles.Therefore,how to improve the power performance and range of electric vehicles as much as possible through reasonable matching of transmission system parameters has become the main research goal of experts and scholars all over the world.This paper will study the matching optimization of electric vehicle power transmission system from three aspects: preliminary parameter matching,speed ratio optimization and shift rule optimization.Firstly,the parameters of the electric vehicle’s transmission system are preliminarily matched by dynamic mathematical modeling.Secondly,the vehicle simulation model of Cruise electric vehicle was built,and the speed ratio and shift rule of the vehicle model were optimized by using adaptive simulated annealing algorithm(ASA).The specific contents of this paper are as follows:(1)According to the basic parameters and design requirements of the electric vehicle,and considering the working characteristics of the motor,using the vehicle dynamics equation,the preliminary matching design of the main performance parameters of the battery,the driving motor and the driveline was carried out.(2)The vehicle simulation model of the electric vehicle was built with Cruise software,and the relevant simulation calculation tasks were formulated with the built vehicle model,and the calculation results of the simulation output were analyzed.Finally,the simulation data results obtained are compared with the design requirements,which verifies the accuracy of the vehicle model built.(3)Adaptive Simulated Annealing Algorithm(ASA)was used to optimize driveline parameters.The transmission ratio of each transmission was selected as the optimization variables,the electric power consumption of the electric vehicle under NEDC condition was taken as the evaluation index of the vehicle economy,and the maximum climbing slope,100 km acceleration time and maximum speed of the vehicle were taken as the evaluation indexes of the vehicle dynamic performance.The mathematical optimization model of the vehicle driveline parameters was established.The speed ratio of driveline was optimized by using ASA algorithm in Isight.(4)Based on the optimal transmission ratio of the transmission system,the opening degree of the accelerator pedal and the shifting speed were taken as optimization variables to optimize the shifting rule of the transmission by using the optimization algorithm.The curves of economic performance,power performance and comprehensive shifting rule were obtained respectively,and the different shifting rule curves were compared and analyzed.The results show that the method of adaptive simulated annealing is reasonable and effective.At the same time,on the basis of the optimal transmission ratio,the shift rule is optimized to further improve the economy and power performance of the vehicle.