Poly-phase motor drives under fault and normal conditions: Application for a five-phase induction motor

Abstract

This paper describes the modelling of the system poly-phase motor and multi-leg converter during normal and under fault conditions. The numerical simulation of the Direct Torque Control (DTC) applied to the five-phase asynchronous machine is presented. In the DTC method, the torque and the flux are imposed directly by a choice discriminating of the vector voltage imposed by the five-leg converter. Our objective is to achieve an effective control as well in permanent regime as in transient one using the combination of different strategies of commutation, to elaborate the most optimal working condition based on the mathematical reports of the special vectors; stator and rotor flux, and stators current and voltage. The implantation of the DTC is conceived on the basis of an algorithm of evaluation of the stator flux and the electromagnetic torque. Both normal and under fault conditions are simulated. Under fault conditions, resulting in loss of one or more phases consecutively, still the machine works with its desirable performance. Most poly-phases machines are used in propulsion maritime, aerospace, naval, railway traction, and in too many applications where the repartition of power is needed. To illustrate the performances of this technique, results by numeric simulation on MATLAB are presented.