Multi-Sector Windings For Bearing Relief E-Machine: Saturation and Cross Coupling Effects

The key driving elements for any electrical machine (EM) used in aerospace and other safety critical applications are the reliability, mass, volume, and efficiency. To reduce mass/volume while satisfying the power required, the option is to increase the EM speed. The possible failure of the mechanical bearings at high speed, the higher bearing losses, and the excessive rotor displacement at high speed are some of the design challenges encountered when the speed increases. The main objectives of applying this MSBRM concept is to achieve the magnetic levitation of the rotor to (a) overcome the bearing reliability issues, as well as eliminating the bearing friction, (b) apply online radial force control on the rotor to mitigate the rotor displacement/whirling, and (c) reducing requirements for maintenance and monitoring. In this paper, the multi-sector windings bearing relief electric machine (MSBRM) concept is applied to high torque density permanent magnet EM. The electromagnetic characterization and the radial force control concept of the highly saturated EM has been studied deeply in this paper.