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This dissertation addresses advanced control methodologies for the five-phase permanent magnet assisted synchronous reluctance motor (F-PMa-SynRM) drive under various open phase fault conditions. F-PMa-SynRMs are principally reluctance-type machines which contain fewer magnets than permanent magnet machines. The major advantage of F-PMa-SynRMs is their inherent fault-tolerant capability, which makes them suitable for critical applications in the automotive and aerospace industries. However, under different open phase faults, F-PMa-SynRMs lose their primary advantages due to reduced average torque and higher torque ripple creating severe vibrations that may cause immediate system shutdown. Additionally, the parameter estimation becomes challenging due to the temperature variations and the presence of current harmonics. In these situations, it is essential to develop advanced fault-tolerant control (FTC) methods for F-PMa-SynRMs targeting the maximization of average torque, minimization of torque ripple, and accurate estimation of temperature. Also, during the FTC, a fault detector is necessary to implement any feedback control methods.An optimal phase advance control method is proposed to maximize the reluctance torque with a minimum phase current under different open phase fault coniii ditions. Then, an active torque ripple minimization (TRM) technique adopting three major steps is proposed as follows: (i) active current harmonic identification, (ii) percentile harmonic injection, and (iii) vector rotation of healthy phases. After that, an analytical method is proposed to estimate magnet temperature in the F-PMa-SynRM without needing any temperature sensors. Finally, this dissertation develops a simplified fault detection method based on five-phase symmetrical component (SC) theory.Extensive simulation using MATLAB and finite element method is done to validate the theoretical claims. For further validation, experiments have been conducted on a 2.9 kW F-PMa-SynRM in different operating conditions. A five-phase IGBT-based inverter, digital control based on Texas Instruments digital signal processor F28335, and a dynamo set-up have been developed to support experimental tests.While applying the proposed FTC, a maximum of 92.2% torque is obtained experimentally under a single-phase open fault condition; in comparison, previous methods could achieve up to 80% torque. The torque ripple is improved from 22% to 11% using the proposed TRM method under the single-phase fault condition. Also, under the two-phase fault condition, 11% improvement is observed in the torque ripple with the proposed TRM method. The magnet temperature is also estimated under different operating conditions, and to have no more than 3.3% error compared to a direct measurement. Finally, the performance of the fault detection method is found to be almost 100% consistent with the theoretical studies.

In this study, optimal fault tolerant control of a five-phase permanent magnet assisted synchronous reluctance motor (PMa-SynRM) has been proposed under different types of fault conditions. Consistent and safe operations of a system are major concerns for critical service applications of electrical motors particularly in the automotive and aerospace industries, and can be achieved through the use of advanced control strategies. The proposed fault tolerant control strategy is based on advanced vector control of the five-phase PMa-SynRM, which provides safe machine operation under various phase-loss fault conditions. The PMa-SynRM utilizes higher reluctance torque through large saliency ratio (ratio of d-axis and q-axis inductances) compared to a conventional permanent magnet motor. The phase currents (magnitude and phases) needed to achieve maximum torque under fault conditions have been derived. The degree of phase advance is varied based on different fault and load conditions, so as to deliver maximum output torque while reducing the phase current amplitudes to lessen saturation effect in the machine. Detailed theoretical analysis and finite element analyses (FEA) simulation have been carried out to verify the proposed method. The proposed method has also been validated through a 5 hp dynamo testing system.