Core Energy Capacitance of EE-Type NiZn Inductor

The increased application of wide-band-gap devices makes the converters smaller and smaller, while the passive magnetic is still the bottleneck. At MHz to tens of MHz range, the stray capacitance of magnetics can affect the operating range and EMI performance of the device. In order to study the stray capacitance of the inductor, the electric field distribution in the core shall be investigated. In this paper, the capacitance model of the core is developed and the electric field characteristics are analyzed for an EE-type core inductor with NiZn material. NiZn cores are generally with low dielectric constant and permeability and is used in the MHz high frequency range due to its low loss characteristics and stable parameter along with the frequency. A general analytical model is derived, and the errors of the model are analyzed and compared with the Finite Element simulation and experimental results.