Investigation of the effects of the mover magnetic circuit geometry of IPM T-LSMs on their no-load features

Abstract

The paper deals with an approach to design the pole shape of inset permanent magnet fractional-slot tubular-linear synchronous machines (IPM T-LSMs). The study is initiated by a 2D finite element analysis (FEA)-based investigation of the effects of the pole-shaping on the machine no-load features. Such investigation is carried out while varying a single geometrical parameter: that is the angle characterizing the inclination of both sides of the pole shoes. The second part of the study focus on the effects of such a design parameter on the no-load features, considering a comparative study between three T-LSM topologies characterized by remarkable pole shapes, namely: (i) “conventional”, (ii) “rectangular” and (iii) “trapezoidal”. It has been found that the pole shaping has a significant effect on the cogging force peak-to-peak value, while it does not affect the back-EMFs.