Comparative Study on Two Modular Spoke-Type PM Machines for In-Wheel Traction Applications

Hengliang Zhang,David Gerada,Guang Zhang,Chris Gerada,Yugang Li,Wei Hua

doi:10.1109/tec.2019.2927872

Abstract

This paper focuses on the comparative analysis of modular spoke-type permanent magnet machines with two magnetization modes, which are referred to as M-I and M-II types. The analytical models of the proposed machines are built based on the simple magneto-motive-force-permeance method. With the help of finite element analysis and the analytical models, magnetic fields in machines with different magnetization modes are compared. Then, taking as a base an existing commercial in-wheel machine used in an electric motorcycle, two proposed machines with different magnetization modes are designed as in-wheel traction machines and compared with respect to electromagnetic torque, flux-weakening performance, over-load capability, etc. The machines are prototyped and experimentally tested to verify the prediction that the M-II machines exhibit a higher torque output whereas the M-I machines have a wider speed range.

Highlights

WITH the development of electric vehicles (EVs), in-wheel traction machines have been attracting more and more research interest, due to their high compactness, efficiency, and operational flexibility
It is found that the M-II MSTPM machine has a slightly higher phase back-electromotive force (EMF) than the M-I MSTPM machine
The magnetic circuit models and PM-MMF-permeance models of M-I and M-II MSTPM machines are built, which results in an analytical solution of both air-gap flux density and torque-sizing equation

Summary

Introduction

WITH the development of electric vehicles (EVs), in-wheel traction machines have been attracting more and more research interest, due to their high compactness, efficiency, and operational flexibility. Extensive studies are reported on the investigation of in-wheel traction machines’ design [1]-[3], analysis [4], [5], optimization [6], [7], and control [8], [9]. The in-wheel machine design, including optimization and topology exploration, has always. In [6], a multi-objective optimization design method of in-wheel switched reluctance machines (SRMs) was developed by using weight factors and in part by the Scientific Research Foundation of Graduate School of Southeast.

Objectives

Methods

Findings

Conclusion