A Simplified Iron Loss Model for Laminated Magnetic Cores

Abstract

This paper presents a new method for the prediction of iron losses in laminated magnetic cores. The method is based on the evaluation of the magnetization curves and loop shapes by which the iron losses, including hysteresis, excess, and classical eddy-current losses, are calculated from the loop area. The purpose of the method is to omit the numerical solution of the nonlinear diffusion equation (resulting from Maxwell equations) while maintaining reasonable accuracy of the iron losses. Therefore, the proposed method determines, using simple concepts, three magnetic field strength components that are responsible for generating the iron losses. The magnetic field component of the hysteresis loss is calculated by a static hysteresis model. The magnetic field component of the excess loss is calculated using the statistical loss theory. Determining the magnetic field component of the classical eddy-current loss is based upon the assumption that the flux distribution in the steel sheet is uniform, but, here, the eddy-current loss is implicitly enforced to be dependent on the magnetic characteristics of the material. The proposed method is applied to the calculation of iron losses in an electrical steel when the accuracy, stability, and generality of the method are discussed.