Torque speed characteristics of switched flux permanent magnet machines

Abstract

Purpose

The purpose of this paper is to investigate the influence of end‐effect and cross‐coupling on the torque‐speed characteristics of switched flux permanent magnet (SFPM) machines.

Design/methodology/approach

The torque‐speed characteristics are predicted using two different methods. These are direct and indirect finite element methods, at different cross‐coupling levels, namely, full cross‐coupling on both PM flux linkage and dq‐axis inductances, partial cross‐coupling on the PM flux linkage only and without cross‐coupling.

Findings

The influence of the cross‐coupling on dq‐axis inductances of the studied machine is relatively small. However, it is more significant on the PM flux linkage. Therefore, the partial cross‐coupling model, which is much easier and faster, exhibits almost the same accuracy as the full cross‐coupling model. Furthermore, the end‐effect causes a large reduction in torque‐speed characteristics. However, such a reduction is more significant in the flux weakening operation region.

Originality/value

This is the first time that the influence of end‐effect of SFPM machines on the torque‐speed characteristics, especially in flux weakening region, and on the dq‐axis inductances has been investigated.

Citation

Zhu, Z.Q. and Azar, Z. (2012), "Torque speed characteristics of switched flux permanent magnet machines", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 31 No. 1, pp. 22-39. https://doi.org/10.1108/03321641211184805