In view of the problem of severe longitudinal flutter occurred during vehicle starting with motor-drive mode in a newly developed hybrid electric car, the vibration source and control scheme are investigated in this paper. Firstly, road test of real vehicle is carried out. The vehicle starts and slowly accelerates with constant torque, the vehicle speed, the rotation speed and current of motor as well as the vibration acceleration of motor housing and seat guide are measured realtime and the frequency feature of flutter is determined with time-frequency analysis. Then based on the measured data of three-phase currents and by using finite element method, the motor torque in experiment condition is predicted and the time-frequency analysis is performed on torque ripple. The results show that it is the forced excitation caused by motor torque ripple at low-speed low-load condition, which leads to longitudinal flutter. Finally measures are taken to suppress the phase current of motor and control its torque ripple, the ride comfort at accelerated starting phase is significantly improved.%针对某新款混合动力轿车在纯电动模式起步存在严重的纵向抖振问题,研究其振动来源和控制方法.首先进行实车道路试验,以恒定转矩缓加速起步,实时采集车速、电机的转速与电流和电机机体与座椅导轨的振动加速度,并采用时频分析法确定抖振的频率特征.然后,利用实测三相电流数据,用有限元法预测试验工况下的电机转矩并进行转矩波动的时频分析,结果表明:低速小负荷下的电机转矩波动引起的强迫激励导致车辆起步加速时的纵向抖振.最后,通过抑制电机相电流畸变控制电机转矩波动,显著改善了起步加速的平顺性.
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