Development of a Lorentz-Force-Type Slotless Self-Bearing Motor

Magnetic bearings have advantages such as no friction loss, no abrasion, and lubrication-free operation. However they are not widely used due to their high cost and large size. In order to solve these problems, a self-bearing motor 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 six-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 rotation speed and radial position of the rotor are controlled by this force. In this study, the rotating torque and bearing force are analyzed theoretically, and a method for their control is discussed. A simple experiment confirms that the proposed self-bearing motor can be realized.