Analysis of Static Characteristics in a Slotless Type Permanent Magnet Machines Based on the Concept of Transfer Relations

摘要

It is well known that the accurate calculation of the field distribution is essential for the design of permanent magnet (PM) machines. The analysis of PM machines have been performed by using finite element method (FEM). However, while FE analysis provides an accurate means of determining the field distribution, with due account of saturation etc., they remain time-consuming and do not provide as much insight as analytical solutions into the influence of the design parameters on the machine behavior. Many analytical techniques have been investigated to predict the magnetic field distribution in PM machines equipped with surface-mounted permanent magnets and 3-phase stator winding. Z.Q.Zhu and D.Howe[1][2] presented analytical solutions of open-circuit field by PM, armature reaction field, etc. And, using the analytical technique by transfer relations, D. L. Trumper[3] and K. R. Davey[4] presented the design and analysis of linear permanent-magnet machines and induction machines, respectively. On the basis of two-dimensional (2-D) analytical solutions derived in terms of magnetic vector potential and 2-D polar coordinate systems, this paper deals with static characteristics analysis of slotless type surface-mounted PM machine. Specifically, using the analytical technique by transfer relations, magnetic field due to PMs and winding current, the back EMF and the electromagnetic torque characteristics are calculated. The validity of the analysis results is confirmed by FE analysis.