A Robust Control Design for Minimizing Torque Ripple in PMSMS for Vehicular Propulsion

Permanent magnet synchronous motors are expected to be applied to propulsion systems of electric vehicles for their high power and torque density, high efficiency, large constant power operation region and cost-effectiveness. However, their large torque ripple is an obstacle in practical applications of PMSMs to vehicle propulsion. The torque ripple reduction of PMS machines for vehicular propulsion (traction applications) has also received great attention because large torque ripple can create uncomfortable vibrations and mechanical damage and cause vehicle noise, and even lead to vehicle instability. Here, our objective is to solve more particularly the problems caused by the torque ripple affecting the mechanical transmission of the electric traction chain. The purpose of this paper is to propose a new control technique of PMSMs for vehicular propulsion by decreasing the torque ripple and improving the dynamic performance of direct torque control using a new sliding mode backstepping control. In this proposed method, the control of the torque and flux, which is designed by the nonlinear backstepping control, replaces the hysteresis controllers in the conventional DTC and the sliding mode control is used as speed controller. The simulation results show that the proposed method can obviously reduce the torque and flux ripple, and can provide better speed tracking performance compared with the conventional DTC, so that the system has satisfactory dynamic and static performance.