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

This paper presents the comparative study of coreless-type permanent magnet linear synchronous machines with nonoverlapping windings. An analytical expression that can be applied to any combinations of pole and coil numbers is developed for evaluating the electromagnetic performances. Subsequently, a simple factor called thrust factor is introduced to find the best Cpp family depending on the variation of coil width ratio. From the comparative study, a significant result is reported that C
_pp
= 1/4, i.e., multiple 4-pole/3-coil, is the best non-overlapping winding configuration of coreless-type permanent magnet machines owing to the highest value of thrust factor. Finally, the validity of the key analyses is confirmed by optimal results, finite element results, and experimental results from prototype machines.