Iron Loss Analysis of Permanent-Magnet Machines by Considering Hysteresis Loops Affected by Multi-Axial Stress

Abstract

This article describes a method to calculate iron loss of permanent-magnet machines by considering the hysteresis loops affected by multi-axial stress. A simple hysteresis model is introduced and modified by reluctivity and hysteresis loss increase ratios, which can be determined by core material experiments under uniaxial stress. This model is coupled with time-stepping finite-element analysis. The validity of the proposed method is confirmed by the core material experiments under multi-axial stress and measured characteristics of permanent-magnet machines. It is clarified that the accuracy of the proposed method is acceptable.