Feature Investigation of a T-LPMSM Following the Selection of Its Slot-Pole Combination

This paper investigates the no-load and the on-load behavior of a fractional-slot tubular-linear permanent magnet synchronous machine (T-LPMSM). The study is initiated by the selection of the machine slot-pole combination. To do so, a formulation of the air gap flux density, based on the solution of the magnetic potential vector equation in the air gap and in the PM regions, is derived. The electromagnetic model allows the prediction of the phase back electromotive forces (EMFs) and of the cogging force. The effect of the slot-pole combination on these features is then considered to the aim of the optimal selection of the slot per pole and per phase. A case study considering the optimized slot per pole and per phase number is treated where the analytically predicted no-load features are validated by finite element analysis (FEA). The investigation is extended to the on-load characteristic which is predicted by FEA and is validated by experiments.