Research On The Key Technologies Of The Electromagnetic Two-Speed Automatic Transmission System Of Electric Vehicle Driven By Dual-motor

Pure electric vehicles can be driven directly by driving motors,and the performance of driving motors determines the performance of vehicles at this time.By analyzing the output characteristics of driving motors,adding to transmission can improve the driving performance of EVs,optimize the performance of power and economy,and broaden the operating conditions of driving motors.Based on the direct drive system of two motors,this thsis proposes to optimize the operation performance of EVs by adding to dual-transmission in the power system.The main contents of this paper are as follows:(1)On the basis of electric drive power system driven directly by two motors of the key research and development project of Shandong Province "Key Technologies Research of Four-wheel Driven Pure Electric Vehicle",the power and economy of it are improved with the two gear dual-transmission without clutch and synchronizer.The structure form and power transmission route of the two-gear automatic transmission are introduced.(2)According to the shifting process of transmission,the shifting process of transmission is divided into five stages,which are unloading of the driving motor,disengaging,active synchronization,shifting and restoring torque of driving motor,to simplify the analysis of the shifting process of transmission,and the dynamic equation is established according to the coordinated position of gears in different shifting stages.It is known that the working mode of controlling the driving motor can realize the whole Shifting process of transmission by analyzing;(3)Permanent magnet synchronous motor(PMSM)is the input part of power.The performance of it determines the quality of gear shifting.In this thsis,a PMSM controller is designed based on the fuzzy PID-IMC control algorithm,to optimize the output of torque and speed characteristics of the motor,and to improve the quality of gear shifting of the transmission.(4)The dynamic and economical shifting laws of pure electric vehicle automatic transmission are formulated by traditional calculation method of shifting laws.The influence of gradient condition on shift law is analyzed,and the shift law is modified.The relationship among the opening,gradient,braking force and correction coefficient of accelerator pedal is established by fuzzy control algorithm.In addition,because of the particularity of the structure of double transmission,the conversion coefficient of curved driving is put forward.The different rotational speeds of the two wheels are equivalent to the speed of the vehicle to realize the function of the differential,so that the shift problem of automatic transmission in the curved driving process can be transformed into the shift problem of the straight running condition.(5)The PMSM control model and shift law verification simulation model were established in the MATLAB/simulink simulation environment.The simulation results show that the control algorithm of fuzzy PID-IMC has certain advantages over the traditional PID control system.Compared with the dynamic shift pattern,the economic shift pattern can improve the vehicle performance and reduce energy consumption.At the same time,the running performance can be improved by modifying the shift law of upslope and downslope running conditions.