Effects of Rotor Position Error on Longitudinal Vibration of Electric Wheel System in In-Wheel PMSM Driven Vehicle

The influence of a rotor position error on the longitudinal vibration of an electric wheel system is analyzed. To begin with, the influence of the rotor position error on the motor current and torque is deduced using coordinate transformation. The results show that the rotor position error will induce current harmonics, which cause further torque ripples with frequencies of kp
_res
/pf
_e
and (6 ± kp
_res
/p)f
_e
(k = 1, 2, 3, p is the number of motor pole pairs, p
_res
denotes the number of resolver poles, and fe indicates the current fundamental frequency). Then, the dynamic model of the electric wheel is established, and the main vibration modes are determined. A comparative analysis of the motor's longitudinal vibration response with and without the rotor position error shows that the torque ripples with frequencies of kp
_res
/pf
_e
deteriorate the vibrational characteristics of the electric wheel system over the entire working range. The torque ripples with frequencies of (6 ± kp
_res
/p)f
_e
increase the motor's vibration at low rotation speeds. Next, the influence rules of rotor position error on the current harmonics and longitudinal vibration are verified by electric wheel bench test. At last, a control method based on adaptive Kalman filter is proposed. This method can mitigate the adverse effects of the rotor position error according to the experimental results. This study provides a reference for the diagnosis of the motor rotor position error and the attenuation of electric wheel vibration.