الفهرس 
Multiphase machines’ advantages and applications
MACHINE MODELLING AND POST-FAULT CONTROLOnly 14 pages are availabe for public view
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Abstract
Three-phase induction machines play an important role in most industrial applications. In high power applications, the multiphase machines have specifically proved to be promising. Thanks to their potential merits over their three-phase counterparts, including less power/current per phase and high fault-tolerant capability. With the accelerated development in semiconductor power devices along with the dictated rigorous reliability standards in some industrial applications, the multiphase machines are expecting to prevail in applications such as electric ships, electric vehicles, railway traction, and wind energy conversion systems. Of the different prominent advantages, operation with some phases open represents the main salient merit of multiphase machines over conventional three-phase machines. Interestingly enough, a pre-fault operation can be still preserved with a proper fault-tolerant controller and a predefined control strategy. To this end, optimal current control using multiple Proportional Resonant (PR) or sync. frame Proportional Integral current regulators are usually employed. The number of PR controllers depends on the number of machine phases and/or the required current quality indices, which adds more complexity while complicating the tuning process.
In this thesis, a new controller is proposed to enhance the torque quality of an asymmetric six phase I.M. under post-fault operation. The so-called Fractional order Proportional Integral (FOPI) regulator is employed to regulate the motor current instead of the widely used PI regulators. The former is known to offer more degrees of freedom while enhancing the system controllability. The response of the new controller is compared with the traditional sync. frame PI controller, where the standard Indirect Field Oriented Control (IFOC) is used to generate the required torque producing (αβ) current components. The reference current components of the secondary subspace are then obtained using predefined optimal constant gains based on the well-known Minimum Loss (ML) optimization criterion. The whole system is modeled and simulated using Matlab/Simulink software under different operational case studies.