The unbalance between parameters of multiphase induction motors is mainly resulted from the variation in the first-phase resistance of stator and rotor. This paper aims to examine the performance of five-phase induction machine with unbalanced parameters. First, a model was set up for the five-phase induction machine, which can efficiently identify the defects in natural frame of the machine. Then, five-phase induction machine were simulated in difference scenarios on Matlab/Simulink. The variations in stator and rotor resistance were measured, and their impacts on several performance indices were analyzed in details. The results show that the variations directly affect the torque ripples, Joule losses, and mechanical speed of the fivephase induction machine. The research findings indicate the possibility to eliminate this effect through fault-tolerant control.

An improved dynamic behavior of water pumping system is presented in this paper. The system consists of a seven-phase induction motor powered by a photovoltaic generator (PVG) and a battery bank, via two static converters controlled independently. A boost converter based on fuzzy logic controller is utilized to adapt the voltage of the photovoltaic generator in order to extract maximum power. A three levels neutral point clamped inverter (NPC) is introduced to attain a low voltage harmonic distortion in the system. In addition, an improved direct field oriented control with minimizing non-sequential currents for the seven-phase induction motor using fuzzy logic filter is implemented. To verify and validate the proposed system, an optimal operating point is chosen to locate the dynamic and static operating limits of the system. Moreover, the proposed system is simulated and analyzed. The minimization of the non-sequential currents component induces a quality energy improvement with minimizing of the Joule losses, which increase the system efficiency. The use of the seven-phase machine brings a degree of additional freedom to the system, its tolerance to faults is a capital issue for the isolated places.

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The polyphase machine provides increased reliability by enabling operation with one or more phases in fault, and the most common faults are stator fault, it's for that a new analysis model of stator open phase faults in a five-phase induction motor has been presented in this paper. A new modeling of five phase induction machine in natural frame is elaborated, and the performance of five phase induction machine was analyzed under stator open phase using the principal component analysis (PCA) method. The PCA is a tool to reduce multidimensional data to lower dimensions while retaining most of the information, where the effect of the fault conditions caused by open phase on electromagnetic torque, mechanical speed, stator current and efficiency of this motor has been investigated. The findings of this research may be useful and help researchers who are interested on the fault tolerant control to minimize or eliminate this effect.