Homothetic Method to Compute Winding Losses in the Design of Power Inductors

This work proposes an improvement for the consideration of ac winding losses in the design process of inductors to be employed in power converters, where the geometrical parameters of the inductors are not known before starting the design. The presented method consists of the pre-computation of a homothetic multivariate regular grid surface by finite element simulations, from which the winding resistance can be obtained by direct multivariate linear interpolation. Special attention is given to Dowell's analytical formulations. These are often used in the design but typically with little details given on how the final expressions are derived. The results with the new method are shown to be more accurate than the analytical calculations over a wide range of design points and, thus, are a useful design tool.