Performance Evaluation and Test Results of a 11,000r/min, 4kW Surface-Mounted Permanent Magnet-Type Bearingless Motor

Recently, bearingless motors are actively developed and researched. The rotor suspension control algorithms have been already proposed and tested by prototype machines. To apply the bearingless motors in industry fields, it is necessary that the performance evaluations as electric motors as well as the rotor suspension characteristics are found. In this paper, a prototype 11,000r/min, 4kW surface-mounted permanent magnettype bearingless motor is constructed. The rotor radial position control method, in which an influence of armature reaction to the bearingless motor magnetic field is considered, is presented. Then, it is confirmed that the rotor shaft is successfully suspended by electromagnetic forces even in a high speed operation. In addition, the motor characteristics of the rotational torque, the efficiency, etc. as well as the necessary power for the rotor suspension are measured by the load tests. The performance of the prototype machine as an electric motor is evaluated by the measured motor characteristics.