SELF-BEARING STEP MOTOR AND ITS CONTROL METHOD

摘要

The present invention relates to a self-bearing step motor, and more particularly, to self-bearing step motor system and a control method thereof, wherein a rotor can be supported by magnetic force without adding an additional winding for supporting the rotor to a step motor having no mechanical bearing for supporting the rotor. The self-bearing step motor system of the present invention comprises a self-bearing step motor including a rotor having a plurality of rotor teeth, a stator having a plurality of stator teeth, a plurality of separate windings wound respectively around the plurality of stator teeth, and a plurality of sensors for measuring geometric deviation of the rotor; and a controller which transforms a torque current for causing the rotor to rotate and control currents for performing a bearing function of supporting the rotor into predetermined supply currents capable of generating magnetic force for allowing the rotor to be supported while causing the rotor to rotate in accordance with outputs of the sensors and position angles of the plurality of windings, which are fed back to the controller, and simultaneously distributes the supply currents among the plurality of windings grouped so that the same phase currents can be supplied thereto. According to the present invention, the self-bearing step motor can replace the conventional step motor. In particular, owing to advantages of the magnetic levitation technology, the self-bearing step motor can be used semipermanently even in a severe environment needed for a super clean and vacuum system without maintenance thereof. Thus, a wide industrial application thereof can be obtained.