الفهرس 
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Abstract
This thesis is concerned with detecting and mitigating the fault effects of Asymmetrical Six-Phase Induction Motor (ASPIM) fed from a Z-source Inverter (ZSI) drive system. The six-phase ZSI has been employed as it has the capability of bucking and boosting which provides wide range of control. Carrier-based PWM schemes with simple, maximum boost and maximum constant boost modulation methods are proposed to control the shoot-through duration of the six-phase ZSI. In addition, a new carrier-based modulator to reduce the inverter switching loss has been proposed. Moreover, a design procedure to obtain the impedance network parameters that keep ripple factors below predetermined values has been developed. The same procedure has been modified in order to obtain the critical allowable parameter values that ensure boosting operation.
In order to guarantee continuous operation of the system under faulty conditions, techniques of post-fault operation have been studied to select the most appropriate one for the current system. To activate the selected post-fault operation, a detection method is needed to localize the fault as soon as possible to avoid more damages. Therefore, Vector Space Decomposition Fault Detection (VSDFD) method has been applied to detect open-circuit faults for the system under study. The dependence of the parameters of this method and their influence on the detection time have been clarified. Recommendation for selecting the method parameters is also introduced. Finally, the performance of the drive system under healthy and faulty conditions is investigated by a series of experimental results that validate the theoretical and simulation study.