Wide frequency range characterization of rotating machine stator-core laminations

Laboratoire des Systèmes Électrotechniques et Environnement LSEE, Université d'Artois, Technoparc Futura, 62400 Béthune, France

Corresponding author: roger@univ-artois.fr

Received: 17 October 2001
Revised: 7 March 2003
Accepted: 8 April 2003
Published online: 17 July 2003

Abstract

In this paper a new method of stator-core lamination characterization, aimed at studying magnetic field in the vicinity of a machine, is proposed. This characterization, made with small signals over a wide frequency range, is useful to study high frequency magnetic behavior of motors fed by PWM static converters. Small minor hysteresis loops of magnetic steel are assimilated to ellipses and, neglecting anisotropy, any point of a stator-core lamination is characterized by two local parameters: the relative permeability and the resistivity. The proposed method consists in measuring the impedance of a test coil over a wide frequency range by an impedance analyzer and in comparing experimental results to theoretical predictions based on magnetic field diffusion equation. An algorithm yields values of local relative permeability and resistivity from inductance measurements and experimental values of resistances are used to control the result quality.