Time-Domain Finite-Element Eddy-Current Homogenization of Windings Using Foster Networks and Recursive Convolution

In this article, we propose an alternative time-domain approach for the homogenization of multiturn windings with frequency-dependent parameters in finite-element (FE) models. First, an elementary 2-D FE characterization of the conductors is carried out over the frequency range of interest to obtain the frequency-dependent parameters and account for the eddy-current effects in the winding. These complex coefficients are subsequently associated with an equivalent Foster network and translated into the time domain via the inverse Laplace transform. The resulting time-domain equations are solved with a recursive convolution scheme. No extra degrees of freedom are required in the homogenized winding. The results of the homogenized model present an excellent agreement with those obtained by an accurate but expensive FE model in which all turns are explicitly discretized. The proposed approach is further compared with a previously developed time-domain homogenization technique based on RL Cauer networks.