Study on a Double-Sided Permanent-Magnet Linear Synchronous Motor with Reversed Slots

The cogging force is a main component of the detent force in the permanent magnet linear synchronous motor (PMLSM). It will lead to the thrust ripple and deteriorate the control characteristics, which cannot be neglected especially in precision machine tools. In order to minimize the cogging force, a novel double-sided PMLSM structure with reversed slots is proposed and compared with a conventional PMLSM in this article. Two novel windings are further added to compensate the unbalanced back electromotive force (EMF) caused by the reversed slots. With this suggested structure, an 8-pole 9-slot double-sided PMLSM is designed. And its detent force and back EMF are evaluated with the help of the 2-D finite element analysis. Finally, a prototype of the double-sided PMLSM with reversed slots is developed, and experiments are carried out to verify the analytical and simulated results.