Analysis of the Dynamic Behavior of Magnetic Materials Under High B and dB/dt

Oualid Messal (1) , Afef Kedous-Lebouc (1) , Olivier Geoffroy (1) , Patrick Mas (2) , Hakim Dhahbi (1) , Christian Chillet (1) , Sebastien Buffat (2) , Sidi Randi (3)

1 G2ELab - Laboratoire de Génie Electrique de Grenoble
2 SE - Schneider Electric
3 Renault

Nowadays, magnetic materials are submitted to extreme working conditions in terms of frequency excitation and induction level. This is mainly driven by scientific and technical requirements to develop compact machines and devices with high power density and efficiency. Therefore, it becomes necessary to have a precise prediction of iron losses in these situations. Several magnetic losses or hysteresis models exist but they often fail to describe the material behavior when both saturation and high flux variation are imposed. This paper focuses on this issue and discusses the influence of the flux density and its time variation ratio on the dynamic magnetic field; B and dB/dt, being the main parameters of the developed models. The study aims to better understand the physical phenomena, to find out the best extrapolation of the material behavior at extreme magnetization conditions and to simplify the experimental identification of models. A progressive approach is considered. Starting from a simple and classical eddy current theory, the dynamic field is first computed under arbitrary frequency considering a linear and nonlinear material. This is carried out thanks to analytical and numerical calculations; the latter being performed with the help of finite element simulations. In all cases, the studies are limited to 2D geometry and the waveform of the average flux density within the material thickness is imposed triangular. In a second step, the steplike magnetization law approach is developed as suggested by Giorgio Bertotti (Hysteresis in magnetism, Academic Press Inc., 1998). In that case the dynamic field is calculated assuming propagating fronts of the magnetization in the material. Finally, an experimental study is carried out in order to highlight all the physical mechanisms including domains dynamics and eddy currents. A thick 50%NiFe sample provided by Aperam Company is chosen to overcome the limitations of the measuring bench met with conventional SiFe alloys. In fact, thanks to its thickness (0.5 mm), high permeability (200000) and low saturation level (1.6 T), high B and high dynamic effects can be easily investigated. Thus, the dynamic magnetic field evolution is analyzed from 5 to 2 kHz under a controlled triangular B waveform and variable level up to 1.55 T.

Domaines: Energie électrique

Oualid Messal, Afef Kedous-Lebouc, Olivier Geoffroy, Patrick Mas, Hakim Dhahbi, et al.. Analysis of the Dynamic Behavior of Magnetic Materials Under High B and dB/dt. Soft Magnetic Materials SMM23, Sep 2017, Séville, Spain. ⟨hal-01589353⟩