电动客车驱动系统机电耦合有限元建模及其响应

Finite element modeling of electromechanical coupling and response in electric bus drive system

电动客车在服役过程中,受到电磁因素与机械因素的共同作用易出现驱动系统不寻常的扭转共振,容易导致齿轮等零部件失效。为探明原因从而解决这一问题,本文尝试从一种新的角度出发,综合考虑电池供电电路、电机电磁力及变速器等整个传动系统中轴的扭转弹性变形之间的机电耦合作用。运用麦克斯韦-拉格朗日方程与有限单元法,分别建立电池-电机子系统动态模型与机械传动系统动态模型,并在此基础上建立电动客车驱动系统的电磁非线性动态方程,再运用Newmark法对整体模型进行数值求解,给出了系统中几个关键节点的时域响应和频域响应。分析结果表明:在电机与变速器连接处的扭振现象较为严重,由于电流输入的不稳定性使得速度与加速度出现异常波动,系统出现频率为22、51、142 Hz的主共振、超谐波共振和亚谐波共振现象。本文可为进一步分析电动客车电传动系统的振动机理提供一种新的理论模型,为解决电动客车驱动系统零件失效的问题提供助力。

In the service process of electric buses,the unusual torsional resonance of the drive system often occurs due to the joint action of electromagnetic and mechanical factors,which easily leads to the failure of gears and other parts.To solve this problem,this paper tries to consider the electromechanical coupling between the torsional elastic deformation of the shaft in the whole transmission system including the battery power supply circuit,the electromagnetic force of the motor and the transmission.Using Maxwell-Lagrange equation and finite element method,the dynamic model of battery-motor subsystem and the dynamic model of mechanical transmission system are established respectively.On this basis,the electromagnetic nonlinear dynamic equation of electric bus drive system is established.Then Newmark method is used to solve the whole model numerically,and the time domain response and frequency domain response of several key nodes in the system are given.The analysis results show that the torsional vibration at the connection between the motor and the transmission is the most serious,and the instability of the current input makes the speed and acceleration fluctuate abnormally,resulting in the main resonance,super harmonic resonance and sub harmonic resonance of the system with frequencies of 22,51 and 142 Hz.This paper can provide a new theoretical model for the further analysis of the vibration mechanism of the electric transmission system of electric buses and help solve the parts failure of the drive system of electric buses.