Frequency-Domain Homogenization for Impedance Characterization of Litz-Wire Transformers in 2-D Finite Element Models

This work deals with a frequency-domain homogenization technique for litz-wire bundles in transformers. The approach consists in adopting a frequency-dependent complex reluctivity in the litz-wire bundles and a frequency-dependent complex impedance in the electrical circuit. The litz-wire bundles become homogeneous conductors which are easy to integrate into a finite element model of a transformer. The magnetic flux and the impedance of the litz-wire transformer computed from the homogenized model agree well with the reference fine model in which each litz-wire turn is finely discretized. The errors of the computed resistance and inductance values are less than 3% and 0.03% respectively with several times faster calculation.Best paper on REV 2016 Eleventh International Conference on Ecological Vehicles and Renewable Energies (EVER)status: publishe