Analysis and Control of Double-Stator Tubular Permanent-Magnet Motor With Series Magnetic Circuit

In this paper, a double-stator tubular PM (DSTPM) motor has been newly proposed, which has two tubular stators and one tubular mover. The magnetic circuits of the inner stator and the outer stator are in series, thus reducing the motor radial length. As a result, the motor volume can be saved, and the motor force capability can be improved. Its topology and electromagnetic performance are presented and analyzed. In order to accurately calculate the cogging force and the end force of the proposed four-slot/seven-pole motor, three slot/pole combinations are modeled and analyzed, namely, 4-slot/7-pole, 8-slot/14-pole, and 12-slot/21-pole ones. Then, the end teeth are optimized to minimize the detent force. A new control strategy is proposed to improve thrust force performance. By using the finite-element method, the proposed motor is verified.