Surrogate model based parameter identification for 3D modeling of common mode chokes

In this paper, we propose a method to provide a wideband 3D model of a toroidal-shaped common mode choke (CMC) and extract the complex permeability curves of the toroid core. The overlapping turns of the CMC’s coils are treated by equidistant turns and external capacitors, while the complex, frequency-dependent permeability is modeled by a 2nd order general dispersion model. Obtaining the optimal capacitance values and dispersion model parameters is addressed as an inverse problem that leads to a minimization of the misfit between the simulated—with 3D finite element (FE) method—and measured transfer scattering parameter curves of the CMC. The computational cost is reduced by a polynomial chaos kriging surrogate model that is built using a small sampling design and is subsequently used as a low-cost substitute for the FE model to support the great number of model evaluations that the inverse problem implies.