Broadband PEEC Model Study on Ferrite-core Inductive Devices of Switched Mode Power Supply

Abstract

Inductors are crucial in power electronics and the real behavior of an inductor can differ significantly from its nominal behavior due to the frequency-dependency of core materials and parasitic couplings at high frequencies. The main difficulty of the broadband partial element equivalent circuit (PEEC) modeling for an inductor is the presence of magnetic materials. In this paper, this electromagnetic difficulty is solved by replacing the magnetized object with a fictitious magnetic current distribution in free space, which is determined according to the boundary conditions. Based on the PEEC method proposed, broadband models of a toroidal inductor and a printed circuit board (PCB) EI core plane inductor in switched mode power supply are established to predict their frequency-dependent impedance. This approach is verified with the results gotten using the finite-element method simulations and measurements. The three models show good agreement for impedance above 200MHz frequency.