DESIGN OF AN ACTUATOR BEING BOTH A PERMANENT-MAGNET SYNCHRONOUS MOTORAND A MAGNETIC SUSPENSION

An original structure of a bearingless motor is theoretically proposed . Using an octopolar permanent magnet synchronous motor, the four acti ve radial axes of a magnetic suspension are generated by supplying som e coils of the motor circuit with additional control currents. Followi ng a given sequence, these control currents have to be modified depend ing on the rotor position in order to give a force that is independent of the rotor position. The most appropriate command strategy is descr ibed and theoretically validated. The working principle does not distu rb the generated motor torque and the functioning of the actuator. The electric drive of this bearingless actuator is studied and the princi pal drawbacks are discussed.