Free-Current-Curve Fault-Tolerant Control of Dual Three-Phase Permanent Magnet Synchronous Motor Under Open-Phase Fault

This article proposes a free-current-curve fault-tolerant control (FCC-FTC) method for a dual three-phase permanent magnet synchronous motor (DT-PMSM) drive system under an open-phase fault. In the proposed FCC-FTC, apart from the basic operational constraints (e.g., limiting the rms phase currents, ensuring torque, and maintaining zero current sum), no sinusoidal phase current constraint is involved while the fault-tolerance performances can be optimized with maximum freedom. According to different torque output commands, the proposed FCC-FTC method can be switched between the Loss Mode and the Torque Mode. In the Loss Mode, the system copper loss can be minimized. In the Torque Mode, the system torque capacity can be maximized. Compared with existing methods, the proposed FCC-FTC method has lower copper loss and stronger torque output capability. An experiment platform is set up on a DT-PMSM, and the effectiveness of the proposed FCC-FTC is validated by experimental results.