Development of Lorentz-force-type Slotless Active Magnetic Bearing

Magnetic bearings have advantages such as no friction loss, no abrasion, lubrication free operation, and so on. However they are not used widely due to their high cost and large size. In order to solve these problems, an active magnetic bearing having a simple structure with distributed windings is proposed. The rotor consists of a permanent magnet and an iron yoke, which rotate in a body. The stator consists of a 3-phase distributed winding and is installed between a permanent magnet and a back yoke of the rotor. A Lorentz-force is generated by the stator current, and the rotor position is controlled by this force. In this paper, the bearing force is analyzed theoretically, and its control method is shown. A simple experiment confirmed that the proposed AMB can be realized.