A Simple and Accurate Analytical Approach for Calculation of Air-Gap Flux Density in PMSM

Permanent magnet (PM) synchronous motors (PMSMs) are being used to drive a number of electric vehicles be it mid-motor or hub-motor. They have high torque density, high efficiency, and a wide speed range. This paper presents a simple, fast and accurate analytical technique for calculating the PM characteristics such as flux density, demagnetizing force, PM energy product and motor characteristics like the air-gap flux density, back-emf, and torque-constant of arc-magnet PMSM. The PM characteristics are represented by a lumped magnetic equivalent circuit when the thickness and width of the PM are increased for the same volume. In this paper, PM characteristics and motor characteristics of Surface-mounted PMSM(SPMSM), Inset PMSM, Interior-magnet PMSM(IPMSM) and Outer-rotor PMSM(Hub Motor) are analytically calculated by the proposed method and then, are compared by finite element analysis(FEA).