VerInA – hysteresis losses in hard magnetic materials used in highly dynamic industrial drive systems

Subject area:

Electrical machines and drive systems

Keywords:

• Computation of electrical machines
• Determination of losses
• Permanent magnet synchronous motor

Description:

In order to excite the magnets in permanent magnet synchronous motors, manufacturers of electrical machines are increasingly turning to neodymium-iron-boron magnets (NdFeB magnets), as they are able to offer extremely high energy density. The disadvantage of NdFeB magnets is that they demonstrate relatively high electrical conductivity, which can lead to high losses as a result of eddy currents that are induced in the permanent magnets by tooth and coil ripples within the air gap. The losses cause the magnets to heat up. Under unfavourable conditions, this can result in irreversible demagnetization of the magnets and the subsequent destruction of the electrical machine.

The calculation of the losses in the magnets is a three-dimensional field issue. As a rule, the 3D finite element method (3D-FEM) offers the possibility of mapping a problem of this nature. However, the variation of the geometric relationships is costly and the calculation is extremely time and cost-intensive, and therefore unattractive for industrial firms. The aim of this research project is therefore to develop a (semi-)analytical computational model to allow the approximate losses in the magnets to be determined during the design phase for the electrical machine.