Coordinated Shift Control and Experimental Study of Two-speed AMT for Pure Electric Vehicle

XIAO Lijun, WANG Ming, ZHONG Zhihua, ZHANG Bangji, XU Weidong


In order to improve the shifting smoothness and to reduce the shifting time of the two-speed Automated Manual Transmission(AMT) equipped on the pure electric vehicle, the mathematical model of the powertrain system was developed, and the comprehensive coordinated control strategies in which the motor participates in the shifting process were designed. The motor torque control law of torque phase was derived from the maximum allowable shift impact,and the PID and finite state switching control strategy were adopted to regulate motor speed during the inertia phase. Additionally, a test rig of the pure electric vehicle transmission system was built for the up-shift and down-shift test. The simulation results show that the up-shift time of 0~100 km/h full acceleration is 0.5 s, the longitudinal impact is within 8.0 m/s3, and the up-shift and down-shift time in the NEDC urban conditions are both within 0.6 s, and the maximum impact does not exceed 7.8 m/s3. The test results show that the up-shift and down-shift time is 0.6 s and 0.8 s,respectively,which is in the condition that the drive motor under fixed speed control, and the output shaft speed changes smoothly. Because the shift time of the traditional AMT vehicle is 0.8~1.0 s, the above results show that the comprehensive coordination shift control strategy can achieve fast and smooth shifting.



Keywords: electric vehicles,  two-speed AMT,  shifting smoothness,  coordinated shift control strategy,  experimental verification

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