Novel bearingless slice motor design with four concentrated coils featuring a unique operational behavior

This work describes a novel bearingless slice motor concept. Being the first bearingless slice motor without permanent magnets in the rotor but in the stator, this magnetically suspended drive system is most suitable for disposable devices in the biomedical, chemical or food industry. Due to the fact that the rotor holds no permanent magnets, it is easy to manufacture and very robust. Additionally, highly acid and high temperature rotor environments can be tolerated without complicated rotor housings. However, it turned out that this drive concept features a new operational behavior distinguishing it from all other state of the art bearingless drives. The considered motor features a biased force orbit, resulting in a superior torque performance when using bearingless slice motors with only four stator coils. After a concept study it was decided to put the theoretical and finite element results to the test. A prototype motor was optimized using a multi-objective evolutionary algorithm, designed, manufactured and put into operation. First measurements verify the finite element simulations and the theoretical considerations.