A Frequency Domain Vertical Dynamics Model of Electric Vehicle Considering Electric Motor Vibration

Aiming at an electric passenger vehicle, a frequency domain vertical dynamics model of electric vehicle considering electric motor vibration with 11 DOF was built. The basic characteristics of transfer functions and power spectral densities of typical vehicle responses were analyzed. The root-mean-square values of vehicle responses under different running speeds and road classes were calculated. From the point of decreasing electric motor vibration and improving vehicle ride, the influence of different mount stiffness, damping and motor mass on above characteristics was analyzed. The results show that the proposed model is able to analyze not only the vehicle ride, but also the motor vibration and its influence on the vehicle ride. The variation of the electric motor parameters has little impact to the vehicle ride, but has obviously effect on the motor vibration. With higher mount stiffness and damping and lower motor mass, the motor vibration will be smaller, although increasing the mount stiffness will slightly decrease the vehicle ride.