Applicability of the Standard Impedance Boundary Condition in the Calculation of 3D Eddy Current Loss in Conductors

The Finite Element Method (FEM) with the standard impedance boundary condition (SIBC) is an efficient approach to calculate the eddy current loss in conducting or ferromagnetic material regions with particular shapes and dimensions. The SIBC is based on the electromagnetic wave theory. In this study, it is demonstrated to be capable of calculating the loss in 3-d regions with different dimensions by comparing with the traditional FEM. The results of different size of ferromagnetic objects show that the relative error of the two methods is within 10%, and the FEM with SIBC provides more accurate results than the traditional FEM. An example of calculating eddy current loss in a transformer using FEM with SIBC is also given.