Fault-Tolerant Control for Permanent Magnet Motors

Five-phase permanent magnet synchronous motor (PMSM) has been widely studied and applied in many industrial fields because of its high efficiency, high power density, and wide speed range. With the improvement of safety and reliability requirements in these fields, it is of great significance to study the multi-phase motor drive system and its fault-tolerant control. Firstly, this chapter takes five-phase PMSM as the research object and makes a brief introduction to the common fault types and control methods. Then, two different fault-tolerant ideas based on the principle of minimum torque ripple and invariable magnetomotive force respectively are analyzed. Focusing on the latter, two methods of fault-tolerant and reduced-order matrix are derived. Furthermore, model predictive control (MPC), vector control (VC), and direct torque control (DTC) are used to realize fault-tolerant control according to the two different matrices. In order to achieve the optimal running state of the motor, the maximum torque per ampere (MTPA) control method based on the fault-tolerant algorithm is also indispensable. The MTPA control methods based on signal injection have high tracking accuracy and good dynamic performance, but the injected high-frequency signal will bring extra torque fluctuation. Therefore, virtual signal injection (VSI) control is more suitable for fault-tolerant algorithms. Finally, VSI-MTPA is adopted to improve the torque output capacity and operation efficiency of the motor under fault-tolerant operation.