Design of a brushless permanent magnet synchronous drive with a merely passively suspended rotor

This paper deals with the design and optimization of a permanent magnet synchronous machine as propulsion of a passively levitated rotation system. Especially the strict conditions regarding the axial and radial stiffness as well as the limited construction space affect the design process significantly. 3D finite element simulations are used to obtain the most efficient drive that fulfills the constraints. Additionally, a passive magnetic bearing is designed, which is capable if compensating the gravitational and load force in axial direction and of stabilizing the rotor in radial direction. After the optimization process, the constructed prototype system is described. The work concludes with measurements validating the accuracy of the simulations.