Tri-mode Fault-Tolerant Control of Three-Phase Permanent Magnet Synchronous Motor Drive System under Single-Phase Open Fault

This article proposes a fault-tolerant controller to achieve uninterruptable operation of a standard three-phase permanent magnet synchronous motor (PMSM) drive under single-phase open-circuit fault. Instead of directly shutting down the whole inverter, the proposed scheme uses the remaining healthy phases for fault-tolerant control. To exploit torque output as far as possible while avoiding overcurrent and over-temperature problems of converters and motor windings, restrictions of the maximum instantaneous current of converters and the maximum rms current of motors are taken into consideration. Based on the post-fault mathematical model of the motor, tri-mode current reference trajectories are designed. The effectiveness of the proposed fault-tolerant controller is experimentally verified, achieving lower torque ripples and speed fluctuations. The proposed fault-tolerant controller does not modify the current controller and can be added to universal controllers easily.