A study on a bearingless drive of a surface permanent magnet synchronous motor

This paper is concerned with a bearingless drive of a surface permanent magnet synchronous motor (SPMSM). Traditional bearingless motors have suspension windings for generating radial forces. But the motor in this paper have no suspension winding. At first, it is shown that a traditional SPMSM can generate a radial force by currents of motor windings. Second, problems and one solution for bearingless drives with a higher speed and larger scale motor are shown. The characteristics of them are numerically clarified with the three-dimensional finite element method (3D-FEM) analysis.