High-Frequency Multi-Winding Magnetic Components: From Numerical Simulation to Equivalent Circuits With Frequency-Independent RL Parameters

In this paper, mathematically rigorous RL circuits of high-frequency multi-winding transformers are identified using an original three-step numerical procedure. They are composed of frequency-independent coefficients and can therefore be introduced in classical circuit simulators. First, the finite-element method in 3-D magnetodynamics, together with homogenization techniques which reduce the overall computational burden, are employed to extract frequency-dependent impedances and voltage gains. Then, the identified equivalent circuit is modified by removing the static resistances from the impedances, so as to obtain frequency-independent voltage gains, or coupling coefficients. An algorithm which is valid for any number of windings is proposed to that end. Finally, the frequency-dependent impedances are identified to Foster networks with constant elements using an optimization algorithm. An experimental validation with an impedance analyzer is proposed.