Open-Circuit Fault-Tolerant Control for Nonsinusoidal Back EMF Five-Phase PMSM With Copper Loss Reduction

Due to the different design optimization, five-phase electrical machines can have a nonnegligible distortion in their back electromotive force (EMF) waveform. Most fault-tolerant control methods for this machine used extra fundamental and third-order harmonic currents to eliminate the torque fluctuation due to the nonsinusoidal back EMF, bringing high copper loss. An open-circuit fault tolerant control using the original transformation matrix is proposed in this article with the objective of converting the parts of torque fluctuations into useful output for copper loss reduction by harmonic current injection. Compared with the previous methods, the proposed method has not only low torque fluctuations, but also the copper loss is reduced by 29% further. Copper loss reduction and the dynamic response of the proposed method are experimentally verified, confirming the advantage of the proposed method.