Speed tracking control design of a five-phase PMSM-based electric vehicle: a backstepping active fault-tolerant approach

Currently, the growing demand for electric vehicles (EVs) makes them one of the fastest-growing sectors in the electricity market. Given that the most important selection criteria for the choice of EVs electric motor drive are mainly related to the reliability, the energy efficiency, and the robustness, five-phase permanent magnet synchronous motor (5P-PMSM) stands out as among the optimal solutions for EV applications. The present paper deals with an active fault-tolerant control (AFTC) for the speed tracking of an EV powered by a 5P-PMSM with sensor failure. The AFTC scheme, integrating an extended Kalman filter (EKF) observer and backstepping controllers, is proposed in order to provide a continuous drive operation of 5P-PMSM even during a sensor fault. The EKF observer is designed to generate the residual signal necessary for the detection stage, whereas speed and current backstepping controllers handle the operating of the 5P-PMSM thanks to their ability to consider the nonlinearities of the system model in generating a control law that is robust and strong enough in healthy and faulty cases. Furthermore, the reconfiguration strategy uses the information received from the fault detection block in terms of the measured and the observed speed signals. To gain the maximum benefit of the EKF observer robustness to random noises and its implementation easiness, both the observed speed and the total load torque applied to the 5P-PMSM and produced by the electric vehicle have been estimated. The analysis results of the conducted simulations show the important significance for the efficiency of the proposed AFTC strategy and prove its high performance in fault detection and tolerant control for enhancing the energy conversion efficiency of EVs powered by 5P-PMSM even under degraded mode, since it significantly outperforms the performance provided by traditional methods.