Comparative Study of Coreless-Type PM Linear Synchronous Machines with Non-Overlapping Windings

This paper provides the comparative analysis of coreless-type permanent magnet linear synchronous machines (PMLSM) with non-overlapping windings. The comparative study is carried out on the basis of conductor winding factor. In order to aid the comparison, the new factor called thrust factor is introduced to denote the best S-pp family depending on the variation of coil width ratio. From the extensive comparisons, an important result is derived that S-pp = 1/4, i.e., multiple 4-pole/3-slot, is the best winding configuration of coreless-type PM machines in the major design domain thanks to the highest values of conductor pitch factor. Three-layer winding configuration, equivalent to traditional full-pitched winding, i.e., S-pp = 1, is also incorporated into the analysis and compared to a single-layer winding configuration. Finally, the validity of the proposed analysis is confirmed by finite element analysis (FEA).