I. Introduction
In power electronic converters, wound components (coils and transformers) play key roles: they provide temporary energy storage, voltage and current transformations, and electrical insulation. In medium and low-power converters, operating frequencies range from 20 kHz to some megahertz; magnetic cores are made of ferrite and, consequently, wound components behave almost linearly. Despite this, these components remain among the most difficult to represent by an equivalent circuit, especially when they own three, four, or more windings.