Basic Research

Soft Magnetic Materials

The use of new, innovative materials at the IEW is a key to improvements and further developments of components and systems.

In addition to the technical understanding of the respective advantages and disadvantages and the associated know-how in the area of production and processing, a basic understanding of business management is also required as to when the use of new technologies and materials is worthwhile and profitable. The IEW is therefore constantly taking up new developments in order to apply basic research in new products for our industrial partners by means of innovative, application-oriented research.

Electrical Machines

Precise knowledge of the relationship between the magnetic flux density B and the magnetic field strength H as well as the remagnetization losses in the material used for the magnetic circuit is a basic requirement for precise calculation and optimization of electrical machines. Therefore, the measurement of material samples is possible and necessary to determine the material parameters required for the simulation on IEW.

To suppress eddy current losses in the stator or rotor, these are usually designed as a stack of laminations. The production of such packages is state of the art and there is a large selection of electrical steel with different properties and in all price ranges. Within the sheet plane, electrical steel has a very high magnetic conductivity, but a very low magnetic conductivity perpendicular to it. In electrical machines with 2D flow guidance, such as synchronous, asynchronous and switched reluctance machines, this is no problem. In machines with three-dimensional flow control, such as transversal or axial flow machines, however, this property is unfavourable. For some years now, IEW has been researching a solution that makes it possible to implement 3D flow control in transverse flux machines by arranging several sheet packages in proven and cost-effective production technology. Current research at IEW focuses on questions such as the modelling of iron losses in such magnetic circuits.

Another material in the field of electrical machine construction, that has so far been used little industrially, is the Soft Magnetic Composite (SMC) material. SMC consists of a pressed and heat-treated metal powder whose individual grains are coated with a thin insulating layer, so that the material has low electrical conductivity and thus very low eddy current losses. Due to the material structure, SMC has the same but comparatively low magnetic conductivity in all spatial directions and, compared to electrical steel, greater iron losses at low frequency. However, the manufacturing process opens up completely new possibilities for shaping and designing soft magnetic components. The use of this material in the magnetic circuit of electrical machines has already been investigated in several dissertations at IEW.

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Institute of Electrical Energy Conversion

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