Bearingless Torque Motor - Modeling and Control

In recent years, demands for magnetically supported direct drives which operate con-tactless and feature a high torque capacity arise in industry. This paper presents an advantageous solution for a bearingless torque motor. The proposed configuration consists of a six phase winding cofiguration with concentrated coils in double star connection to keep power electronics efforts to a minimum. The six phase winding system generates simultaneously both, the actively controlled motor torque and the radial bearing forces for radial position control. The disk shaped hollow shaft rotor carries 26 permanent mag-nets. To reduce the systems costs, tilting de ection and the axial position of the rotor are stabilized passively by the magnetic reluctance forces. The mathematical model and an appropriate control for current and voltage drivers is introduced. Finally, the prototype motor is shown with special attention to the angle and rotor position sensor evaluation.