A Homogeneous Model for Estimating Eddy-Current Losses in Wound Core of Multilevel-Circle Section

The primary objective of evaluation of eddy-current losses is to provide a guide for optimized design of tractive transformer. It is not sensible to directly create the detailed laminations of a transformer core for analyzing the eddy-current field because of sophisticated modeling procedure and incredible computational cost. As a result, in this article, a series of original formulas to describe the equivalent electromagnetic parameters of multilevel-circle-section wound core under various frequencies, including anisotropic conductivity and permeability, are proposed to serve for finite-element analysis, on which the core model is considered to be a continuum with homogeneous material property. The experiment of core losses on practical wound core with the characteristic of multilevel-circle section is taken to verify the availability of the proposed model, where the modified extrapolation method is applied to obtain the eddy-current components separated from total core losses. Finally, there are satisfactory precisions on simulated results of eddy-current losses at a wide range of frequency and magnetic flux density; hence, this homogenization method is effectively applicable for engineering. This article can also provide reference for analysis of the other electromagnetic problems in tractive power supply equipment.