PM Flux Analysis and Thrust Density Enhancement of A Transverse-flux Flux-reversal Linear Motor for Transportation System

Transverse flux linear motor (TFLM) is one interesting research object, which owns the high thrust density characteristic because of the decoupling of electric and magnetic loadings. Among various TFLMs, the transverse-flux flux-reversal linear motor (TF-FRLM) is an excellent choice with both considerable force density and low cost in the long stroke applications, in which the secondary is passive and all the expensive components (e.g., permanent-magnets and coils) are fixed on the primary. Aimed to deal with the low effective PM flux drawback and enhance the force density of TF-FRLM, an improved TF-FRLM topology is proposed in this paper. By adding the auxiliary cores into the blank space of the secondary, the thrust force density of the motor is significantly increased, without any impacts on the space of the armature winding and the PMs. Firstly, the analysis of the PM flux is done to point out the main influence factor on the low effective PM flux. Then, the detailed evolution process of the proposed topology is introduced, and the basic electromagnetic performances of TF-FRLMs are compared by the three-dimensional finite element method. Finally, the enhancement effect on the thrust density of the proposed motor is verified by the prototype experiment.