A principle and test results of a novel bearingless motor with motor parallel winding structure

A novel winding structure of bearingless motors has been proposed for radial force generation. Additional suspension force windings are not needed in stator slots. All conductors are effectively used for both motor torque and suspension force generations, simultaneously. Original motor coils are connected in parallel, however, these are differentially connected in series from the suspension inverter terminals. Thus, speed induced voltage caused by rotor rotation is cancelled so that suspension terminal voltage is reduced as in the case of conventional bearingless motors with separated differential suspension winding. A test machine has been developed and test results are presented.