Active Suppression of Low-Speed Vibration in Electric Vehicle Drivelines Considering PMSM Torque Ripple

Low-frequency torque ripple in automotive permanent magnet synchronous motors (PMSMs) can induce driveline vibration, thereby degrading the driving experience in electric vehicles. To address this issue, this paper employs the lumped parameter method to establish a dynamical model of a typical driveline system and derives its transfer function, elucidating the frequency distribution of vibration under the influence of torque ripple. Subsequently, finite element analyses are conducted to obtain numerical solutions for PMSM torque ripple, considering factors such as slot effects, core magnetic saturation, and non-sinusoidal magnetic fields. An accurate analytical model of torque ripple is developed by combining two-dimensional Fourier series expansion and polynomial fitting. Afterward, a control system integrating reference harmonic current computation and harmonic current tracking is designed to actively suppress the driveline vibration. Finally, the proposed methods are validated through simulations and vehicle testing, demonstrating a significant reduction in motor speed fluctuation and vehicle jerk, effectively improving driving comfort at low-speed starts.