Research On Improving Thrust Performance By Unequal Teeth Structure In Permanent Magnet Linear Motor

In order to improve the positioning and tracking accuracy of the system in linear travel, high thrust performance of the permanent magnet linear motor (PMLM) is required. The application of unequal teeth with alternate winding structure in PMLM is proposed in this paper. The advantages of alternate winding structure are analyzed. The expressions of cogging force and electromagnetic thrust are deduced, and the reason why this structure can improve the thrust performance of the motor is explained. At last, an 18-slot 12-pole alternate winding PMLM is taken as an example, and the thrust performances with unequal teeth and equal teeth are simulated and analyzed. The results obtained by finite element analysis show that the unequal teeth with alternate winding structure can reduce the average magnetic flux density of teeth and the core loss, weaken the thrust ripple greatly and improve the electromagnetic thrust and the fault tolerance capability of motor.