Ripple reduction of torque and suspension force in magnetic levitation machines that enable low speed and high torque drive

In this research project, (1) the effect of armature reaction on the generation of magnetic suspension force and (2) the effect of magnetic gear ratio on the torque ripple were investigated for the proposed consequent pole type bearingless vernier motor. From the voltage equation of the proposed motor, the relation between torque and current and the relation between magnetic suspension force and current were derived. From the derived equations, it was clarified that (A) the magnetic suspension force of the proposed motor can be supported by DC current as well as the conventional consequent pole type bearingless motors, (B) the direction of the magnetic suspension force is biased by the armature reaction, and (C) the order of the torque ripple is the least common multiple of the gear ratio Zr/p and the number of stator teeth Zs.