Extension of Space-Vector-Signal-Injection-Based MTPA Control Into SVPWM Fault-Tolerant Operation for Five-Phase IPMSM

This article presents a new fault-tolerant drive for a five-phase interior permanent magnet synchronous machine (IPMSM) to achieve the maximum torque per ampere (MTPA) operation under open-circuit faults. In the postfault space vector pulsewidth modulation strategy, the voltage vectors are reconstructed by the reduced-order transformation matrix, which is derived from the optimal reference fault-tolerant currents under single-phase and double-phase fault. The z subspace is particularly controlled to reduce the total harmonic distortions of current under single-phase fault, and the distributions of space voltage vectors are established to realize the fault-tolerant operation under double-phase fault. Meanwhile, the high-frequency signal is injected into the space vector under fault condition inherently to detect the MTPA points. Therefore, this method is parameter independent in the tracking of the MTPA point under postfault operation. Besides, the proposed method can effectively reduce the amplitudes of the fault-tolerant currents and improve the torque and efficiency performances compared with $i_{d}= 0$ fault-tolerant control. Finally, on an IPMSM prototype drive system, the effectiveness of the proposed method is verified by the experiment.