Axial position and speed vector control of the inset permanent magnet axial gap type self bearing motor

Magnetic bearing motors have many advantages such as no friction loss, no abrasion, lubrication-free quality, very high speed and so forth. However, they are not widely used due to their high cost, complex control and large size. In order to solve these problems, a self-bearing motor is a reasonable trend in current researches. This paper will introduce an inset permanent magnet type axial gap self bearing motor, which is an electrical combination of an axial thrust bearing and an axial flux motor, as well as the method of controlling axial position and rotating speed of the motor. First, the axial force and the motoring torque are analyzed theoretically and then the control method is derived. In order to confirm the proposed technique, a motor has been made and tested. The experimental results confirm that the motor works stably with the proposed vector control, and the rotating torque and the axial force can be controlled independently.