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

To solve the problems of asymmetry and coupling in the motor's mathematical model under open-circuit fault (OCF) conditions and to improve the fault-tolerant control performance of the non-phase-shift dual three-phase permanent magnet synchronous motor (D3-PMSM), an open-circuit fault-tolerant control strategy is proposed. First, the post-fault decoupling mathematical model of the D3-PMSM under a single-phase OCF is derived in the s-e coordinate system. In order to simplify the torque equation, eliminate the second and fourth harmonics, and achieve decoupling of the inductance matrix, the coordinate transformation is reconstructed according to the principle of constant magnetomotive force. Then, in view of the deficiencies of the minimum loss (ML) and maximum torque (MT) fault-tolerant control strategies, the copper optimization of torque operating range (CO-TOR) strategy is proposed. Additionally, the experiments are conducted to verify the proposed control strategy, and it is compared with the traditional ML and MT fault-tolerant control strategies. The results indicate that, compared with the other two control methods, the proposed method reduces the torque ripple after OCF in D3-PMSM, lowers losses while maintaining the output torque, and demonstrates the good steady-state and dynamic performance.