Influence of flux gaps on the performance of modular PM linear synchronous motors

More and more modular electrical machines, including segmented permanent magnet machines, are being applied in industrial areas to simplify manufacture process and improve fault-tolerant ability. This paper investigates a novel modular single-sided flat permanent magnet linear synchronous motor (PMLSM) with segmented armature. In the armature, the inevitable flux gaps between segments are inserted to enhance the performance of PMLSM. Based on 2D finite element analysis (FEA), the performances, such as open-flux linkage, back-EMF, average thrust force, thrust ripple, etc. are compared in different values of flux gaps, as well as different slot/pole number combinations. Due to flux gaps, it is found the electromagnetic performances are worsened along with flux gap width increasing to modular PMLSMs having slot number lower than pole number, but some aspects of performances can be improved to those having slot number higher than pole number. Due to the end effect of linear format, the thrust ripple is not significantly improved. Finally, to show the difference of linear motor, the detail comparison is made between modular PMLSM and rotate PMSM. It is concluded the proper flux gaps can be chosen to improve the performance of PMLSM with certain slot/pole combination.