Integrated Optimization Of Two-speed System Parameters For Electric Vehicle Without Power Interruption And Control Strategy

With the advantages of less pollution,low noise and high energy conversion rate,electric vehicles have gradually attracted the attention of the government and various automobile manufacturers.However,the range of electric vehicles is relatively short compared with the traditional fuel vehicles,which has become one of the important reasons to limit its popularity.At present,almost all the transmission systems of electric vehicle were equipped with a fixed speed ratio reducer.The driving motor can not always work in its high efficiency range.Meanwhile,the maximum output torque of the vehicle is limited,which can not meet the requirements of power and economy of electric vehicle simultaneously.The multi-gear reducer can solve this problem well.Therefore,on the premise of considering the processing cost and performance requirements of electric vehicle reducer,a new two-speed transmission system is developed,which can ensure that the vehicle can complete the non-power interruption shift.Firstly,the parameters of the two-speed transmission system are optimized and matched,and then the corresponding shift control strategies are formulated for different driving modes in order to improve the overall performance of electric vehicles.Firstly,on the basis of in-depth study of the existing two-speed transmission system,a new type of non-power interruption two-speed transmission system is developed.Then the structure and working principle of the two-speed transmission system are introduced,and the initial parameters of the two-speed transmission system are obtained by preliminary matching based on the basic dynamic requirements of the vehicle.Secondly,based on the analysis of the performance evaluation index of electric vehicle,an integrated optimization model of two-speed transmission system parameters is established,which aims at the acceleration time of 0-100 km/h and the energy consumption of working condition.The integrated optimization model of two-speed transmission system parameters is constrained by shift jerk.The model is solved by simulated annealing particle swarm optimization algorithm,and the optimal parameter combination of two-speed transmission system is obtained.Thirdly,according to the various working conditions of EV,the dynamic analysis of EV is carried out,and the driving mode of EV is re-divided.Then,the driving mode of EV is identified by using the fuzzy control method,and the power and economic shift control strategy of EV is formulated.On this basis,the goal of acceleration time of 0-100 km/h and energy consumption under working conditions is established.The optimization model of comprehensive performance shift strategy for two-speed transmission system is established and solved.Finally,the whole vehicle simulation model and the 0-100 km/h acceleration time simulation model were built,and the results of parameter optimization matching and shift control strategy optimization were simulated respectively.The results show that the electric vehicle with two-speed transmission system performs better in power and economy.