Iron losses computation for ferrites and powder cores

Introduction

Ferrites and iron powders represent a successful strategy to limit losses in magnetic cores, as well as the usage of stacked laminated steel sheets. In Flux, the evaluation of iron losses for these laminated sheets can be performed in all magnetic applications in post-processing thanks to Bertotti model and in some specific cases also with LS approach.

For bulk materials, Preisach and Jiles-Atherton methods have already been available in Flux transient magnetic applications, allowing the user to model hysteresis phenomena and thus compute the iron losses through the dPowV quantity. This approach, even if very accurate, can be costly, especially in 3D simulations.

To save computation time and memory resources, starting from 2025 version, for ferrites and powder cores Flux also features a post-processing iron loss model which applies on magnetic non-conducting regions with non-hysteretic B(H) materials in Steady-State AC magnetic applications (excluding 2D-axisymmetric domains).

Iron loss model

This iron loss model is based on two contributions: the hysteresis and the classical (due to eddy currents) terms, for which the user has to provide the coefficients k and the exponents $\alpha$ and $\beta$ .

The implemented equation for the mean loss density:

complies with the expressions provided by ferrite and powder manufacturers in their data-sheets.

But, since they often use specific units to express the loss density, a conversion of the coefficients k is nevertheless required beforehand to fit with the Flux model, which requires the frequency f be expressed in hertz (Hz), the magnetic field density B_max in teslas (T) and the loss density dP in watts per cubic meter (W/m³).

Iron losses dialog box

To access to the iron loss computation click on :

Computation > Computation of iron losses > Iron losses on ferrites or iron powder losses

Iron Losses Results

As a result, Flux provides two spatial quantities enabling the user to plot the isovalues of the losses and the associated energy in the selected regions, as well as a numerical result containing the whole iron losses integrated over the volume region, with the hysteresis and the classical terms: