Core Energy Capacitance of NiZn Inductors

In the high-frequency (3–30 MHz) range, NiZn cores are commonly used. They have much lower permeability and permittivity than materials typically used at lower frequencies, including MnZn ferrites. Previously used capacitance models rely on the perfect electrical conductor assumption. They are not applicable when NiZn cores are used. We propose a general core energy capacitance model found by solving the electric field boundary value problem. We also propose a simplified model by curve fitting to finite element analysis data. Both are verified by simulation and experimental results in two case studies with rod and pot core structures.