One Phase Open Circuit Fault-Tolerant Control Strategy of Three-Phase Permanent Magnet Synchronous Motor Considering Torque Loss

When one phase fault occurs in a three-phase permanent magnet synchronous motor (PMSM), maintaining system operation under fault conditions through fault-tolerant control algorithms can save redundant hardware and reduce volume, but unnecessary torque losses exist. To address this problem, this paper proposes a current control algorithm to reduce torque losses. Firstly, the torque equation of the motor under one phase fault is derived, and the relationship between the rotor position angle and the stator current under ideal torque is obtained, and an ideal stator current function relationship is designed. Then, the formula for the maximum current change of the actual motor is derived, and the rotor position angle change interval of the function is designed accordingly, and an effective average output torque index formula is designed to calculate the torque loss of the system. The fault-tolerant current control algorithm is experimentally verified on a motor controller based on the DSP chip TMS320F28335 and a 4-kW motor-to-trailer bench. Simulation and experimental results demonstrate that the algorithm can eliminate the excess target torque when the system experiences one phase fault, reduce the second harmonic contained in the torque, and effectively reduce the loss of output torque.