Fast Estimation of Eddy Current Power Losses in Soft Ferrites Rings

Ferrite cores are widely recognized as the most effective magnetic materials for medium to high-frequency power electronic applications due to their low losses in dynamic conditions. However, there is an increasing demand for further improvements in their composition and manufacturing processes to reduce losses at the frequencies used by modern electronic switching devices. This is essential for achieving significant reductions in the weight and volume of magnetic cores in contemporary power electronics. To address this need, an efficient tool capable of accurately predicting eddy current losses in ferrites becomes crucial. In this study, we propose two simplified approaches in the frequency domain for modeling these losses in ferrite cores with a toroidal shape. Additionally, we demonstrate how these models can be extended to the time domain and applied to non-sinusoidal signals. The key material parameters—geometric, electrical, and magnetic—required for running the models are measured. We then compare the performance of these models against experimental measurements taken from three different commercial MnZn ferrites (N30, N87, T38) across a broad frequency range (100 kHz to 2 MHz). Furthermore, the T38 ferrite is also evaluated under non-sinusoidal operating conditions. An in-depth analysis of the results is presented, providing insights into the performance of the models for each ferrite material.