An Approach to Predict IPM T-LSMs Air Gap Flux Density: Application to the Mover Geometry Sizing

The paper introduces an analytical approach to predict the no-load flux density spatial repartition of inner permanent magnet tubular-linear synchronous machines (IPM T-LSMs). It considers a trapezoidal waveform whose maximum value is predicted using a simple magnetic equivalent circuit of an elementary part of the machine. Then, the accuracy of the proposed approach is enhanced by the incorporation of a mover permeance function that accounts for the PM luxconcentrating arrangement. Following its validation by a 2D finite element analysis (FEA), the proposed approach is applied to the investigation of the impact of the mover geometry on the air gap flux density with emphasis on the mover pole shoes by distinguishing the cases of rectangular and trapezoidal shapes. This makes it possible the selection of an IPM T-LSM with appropriate mover geometry for which further investigation of the no-load operation is achieved onsidering FEA as well as experiments carried out on a prototype.