Design of a Bearingless Permanent Magnet Synchronous Machine for High Speed Applications

Abstract:
In this paper the design aspects of a Bearingless Permanent Magnet Synchronous Machine (BPMSM) for high speed applications are presented. The aim of the BPMSM design is a mechanical power of 10 kW at a speed of 100.000 rpm. The main focus is on the dimensioning of the electromagnetic assemblies of the drive and radial bearing unit including the design of the rotor. The sizing of the permanent magnets will be considered as well as their retaining sleeve, which additionally requires the calculation of contact forces between the magnets and the rotor shaft. In order to meet this challenge, the design process of such high-speed machines has to be considered as a multi-physics problem. The analysis of the machine behavior was carried out by means of FEA simulation. Thereby the distribution of magnetic flux density, torque, suspension force and electromagnetic coupling of the motor and suspension windings are simulated. A first prototype for the evaluation of the electromagnetic assemblies is presented. This enables the verification of the FEA model. Finally, the first comparative measurements of the induced voltage of the drive winding and the effective torque are carried out.