A novel magnetizer for 2D broadband characterization of steel sheets and soft magnetic composites

The magnetic materials used in embedded applications need characterization and modeling in the kilohertz range. This problem is well addressed under conventional alternating induction, but with rotational and two-dimensional induction loci, which are ubiquitous in electrical machines, there is lack of results, because of the difficult task of reaching such high frequencies at technically interesting induction values with the conventional laboratory test benches. To overcome this difficulty, a novel three phase magnetizer has been designed, exploiting 3D finite element calculations, and applied in the lab. This device permits one to measure magnetization curve and losses in soft magnetic steel sheets and soft magnetic composites under alternating and circular induction up to about 5 kHz. We provide a few significant examples of loss measurements in 0.20 mm thick Fe-Si and Fe50Co50 laminations, and in soft magnetic composites. These measurements bring to light the role of skin effect under one- and two-dimensional fields.