| In the face of increasingly severe energy crisis and environmental problems,the promotion of new energy vehicles is increasingly valued and supported by governments.Among them,pure electric vehicles,with its excellent handling and zero pollution characteristics,has always been favored by the majority of consumers,and have become a hot research and development and promotion of major automotive enterprises.However,due to the current battery energy storage level,the cruising range of pure electric vehicles is obviously insufficient compared to other models.Under the limitation of existing conditions,it is of great research significance and commercial value to improve the efficiency of electric vehicle drive system to extend the cruising range of electric vehicles.Firstly,this paper analyzes the route of optimization technology of electric vehicle drive system at home and abroad,compares each scheme and chooses the dual-motor structure vehicle as the direction of the optimized route of this paper.Through the analysis of related patents,literatures and products of domestic and foreign dual-motor structure vehicle,Select the layout of the dual motor front and rear drive.Based on this technical route,a four-wheel drive system with dual motors is designed for a domestic vehicle with known parameters,and its drive and brake control strategies were analyzed to study the energy-saving potential of the dual-motor drive system.Firstly,according to the design requirements of the model,and based on the method of energy consumption analysis under cyclic working conditions,the selection of the front and rear motors is completed,and the relevant parameters of the driving system are designed and verified by simulation.Then,according to the efficiency map data of the front and rear motors,the optimal driving efficiency model of the drive system is established,and the particle swarm optimization algorithm is used to solve it.The three-dimensional numerical matrix of front and rear motor output torque T,vehicle speed u and accelerator pedal opening k is obtained.The joint simulation model of Matlab/Simulink and CRUISE is established.The result of efficiency optimal drive control strategy is compared with the CRUISE dual motor default control mode and the single motor drive scheme to verify the energy saving effect of the dual motor drive system and the effectiveness of the optimal drive strategy.Based on this,the brake control strategy of the dual motor drive system is analyzed.According to the relevant theories and regulations,the braking force distribution characteristics of the front and rear axles during vehicle braking are analyzed,and the optimal mathematical model of the dual-motor braking system efficiency is established.According to the optimal efficiency fitness value and corresponding constraints,the solution is obtained.The numerical matrix of the double motor braking torque T and the vehicle speed u and the brake pedal opening b is obtained,and compared with the braking force distribution of front and rear motors schemed by line I and single motor,to prove the correctness of the efficiency optimal braking control strategy,and the energy-saving potential and endurance capacity of four-wheel dual motors are fully evaluated. |
