Lightweight Rotor Shaft for PMSM

The aim of the project was the identification of benefits of Additive Manufacturing (AM) in electric engineering and especially the implementation of this benefits in a Permanent Magnet Synchronous Motor (PMSM)

An optimal material was determined (H13) and its mechanical and electromagnetic properties were investigated and improved by a heat treatment. A suitable PMSM was selected and its rotor shaft design was optimized for AM. The rotor shaft was built out of H13 and mounted into a given stator. Finally the motor characteristics were determined.

The promising results of the motor characteristic determinations showed that the weight of the rotor shaft could be reduced by 25,1%. This leads to a reduction of the moment of inertia of 23% and an reduction of the acceleration time of 23,2 %. The Investigations were performed at 71,98 Nm and 3000 rpm. Moreover the permeability of the material H13 could be improved through a heat treatment. So the permeability could be enhanced from 32 to 480 and the coercivity could be reduced from 5600 A/m to 1300 A/m. This lead to an obvious enhanced soft magnetic behavior.

The project was funded by the Forschungsvereinigung Antriebstechnik (FVA, engl.: Research Association Drive Technology).

Specific the work group “Geregelte Elektroantriebe” (GEA, engl.: Controlled Electric drives) with its industrial members like Siemens, Wittenstein, Porsche, VW, Wilo. The scientific partners were the chairs IAL (University of Hanover) and the IAM (Karlsruher Institute of Technology)