A New Approach for Modeling of Hysteresis in 2-D Time-Transient Analysis of Eddy Current Using FEM

Eddy current is the origin of resistive loss in magnetic cores. In conventional method of eddy loss calculation, flux density is assumed to be distributed uniformly. However, the eddy-current forces the magnetic flux to flow through the skin of magnetic core, the effect that is called flux skin effect. For wave forms other than the sinusoidal form or for non-linear relationship between H and B, there is not analytical solution for the field equations. In such cases, magnetic field and the eddy-current equations must be solved by numerical methods such as finite-element method. Moreover, numerical modeling is helpful in estimating the eddy-current patterns that are used in non-destructive tests to detect the presence of any possible cracks. In order to achieve the flux distribution in the presence of the eddy current, the diffusion equation should be solved. This paper presents a new approach for finite-element analysis of 2-D diffusion equation. The solution is in time-domain, and the hysteresis behavior of ferromagnetic material is included in it. Analysis results show that skin effect has considerable influence on the eddy and hysteresis losses. Presented method has the capability of eddy-current analysis for any shape of cores, including hysteresis behavior.