The effect of third-harmonic of the AIR-GAP MMF on inductance determination in five-phase synchronous reluctance motor

The effect of the third harmonics of the air-gap magneto-motive force on inductance determination using the winding function model is discussed. The representation of the multi-phase other than the three phase machine inductances takes more than a simple sinusoidal expression, as can be observed in the five-phase machine. The various considered models of utilizing the third harmonics of the air-gap magnetomotive force, neglecting the third harmonics and a sinusoidal model of utilizing the third harmonics are presented. These various models inductances computation are used to determine the machine parameters of speed and torque, and their characteristic performance at start-up, loading and faulted conditions are investigated. The MATLAB/SIMULINK software is used for the analysis and implementation of the direct-phase variable model of the machine. The obtained results from the various considered models shows similar relationship sufficient for electric machine analysis, but a more accurate performance characteristics is observed with the configuration utilizing the third harmonics of the air-gap MMF.

I. Introduction

The synchronous reluctance machine operates utilizing reluctance torque for energy conversion, thus desiring a high saliency ratio between the d-axis and the q-axis inductances.