Supplementary materials: Comparison of Three-Winding Transformer Model Extraction Using FEMM and COMSOL Multiphysics®

This research focuses on simulating a transformerusing electromagnetic field solver software: FEMM and COMSOLMultiphysics®. These tools are used to simulate and extractthe model of a three-winding transformer. The primary objectiveof the extracted model is to predict key magnetic parameters,such as leakage and magnetizing inductances. These inductancesplay a critical role in switch-mode power converter topologies,ensuring proper operation and achieving high efficiency throughzero-voltage or zero-current switching. In this study, the transformer,based on an ER28/14/11 core, is simulated using bothFEMM and COMSOL, with the resulting models comparedto each other and experimental measurements. FEMM is afree, 2D solver, while COMSOL is a commercial, 3D solver.This research aims to evaluate the feasibility of using the noncommercialFEMM tool to simulate complex transformer coreshapes. Transformations of the E, ER, and ETD core types forsimulation in both 2D axis-symmetric and planar problem typesare also proposed.