Analysis of Multiphase Permanent Magnet Motors via Space-Harmonic Model

Abstract

Multiphase permanent magnet motors are gaining popularity thanks to their advantages, which include reduced torque ripple, enhanced torque capability, and fault tolerance. However, their modelling and control is more complex. Different harmonics in multiphase motors are separated in different orthogonal planes, each one having a different inductance value. This has different implications in airgap flux and torque generation. In this work, we present a space-harmonic model to analyse the torque production and the inductances in multiphase motors. This contributes to understand the interaction between different harmonics and their implication on the motor characteristics, which can be helpful for the motor design. To further verify the results, a three-phase and a dual three-phase motor are compared with finite element models. The case study confirms the results obtained from the space-harmonic model.