Extended 2D magnetic equivalent circuit method

Abstract

Purpose

The purpose of this paper is to devise a magnetic field modelling approach suitable for simulating the transient behaviour of a class of electromagnetic systems (particularly linear synchronous motors).

Design/methodology/approach

The classical 2D magnetic equivalent circuit (MEC) approach is extended by separately accounting for leakage flux from highly permeable polygonal regions (where the MEC approach is most applicable). It capitalises on the computational efficiency of an MEC approach for regions where the flux can be assumed to be uniformly channelled through a coarse network of “flux tubes” and accounts for leakage flux from these regions by introducing mutual permeances. These mutual permeances are geometry dependent and can be calculated upfront using a surface‐current representation of the magnetomotive force attributed to each flux tube.

Findings

As demonstrated with a simple example, the magnetic field solution converges with an increasing subdivision of flux tubes, yielding a transparent trade‐off between simulation time and accuracy.

Research limitations/implications

Using Schwarz‐Christoffel mapping to approximate the mutual permeances is restrictive and introduces unnecessary error. Hence, the use of finite element or boundary element methods to obtain these permeances is under investigation. Furthermore, it is expected that introducing 2D flux tube elements for junction regions would be beneficial.

Originality/value

A novel approach is presented that aims to improve the accuracy of a traditional MEC solution, whilst retaining its computational advantage for the flux that is well channelled. The method has particular merit for the dynamic modelling of linear motors, where the machine's behaviour is dominated by the flux bridging the air gap.

Citation

Lines, C.R., Cronjé, W.A. and Wigdorowitz, B. (2010), "Extended 2D magnetic equivalent circuit method", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 29 No. 6, pp. 1435-1443. https://doi.org/10.1108/03321641011078508