Research On Induction Linear Motor For The Rail Train

Most of the stations where urban rail trains run are densely distributed.During operation,there are not only a large number of speed regulation processes,but also frequent switching between acceleration and braking processes.Among the existing wheel rails and low-speed maglev trains,the single-sided linear induction motor(SLIM)is applied most frequently.Therefore the SLIM is selected for research in this paper.This paper introduces the development of SLIM home and abroad,analyzes the force and eddy current distribution of the existing SLIM according to the operation principle and secondary structure of SLIM,points out the defects of the existing SLIM secondary structure in terms of electromagnetic thrust and electromagnetic braking force,and proposes an improved SLIM secondary structureAccording to the rotating motor theory,by introducing the equivalent magnetic pole logarithm,the two typical improved primary and secondary slot coordination relationships are compared,the application scope of the slot fit theory in the rotating motor in SLIM is obtained,the effect of the improved 6 slot fit relationships on the electromagnetic thrust is analyzed,and finally a slot fit with the least harmonic influence is determined and its mechanical characteristic curve is obtained.The electromagnetic design method of the improved SLIM is given,the improved equivalent circuit is corrected,the calculation formula of the parameters and related electromagnetic characteristics of the improved equivalent circuit is derived,and the 40.5k W improved SLIM example design is completed.In the ANSYS finite element simulation environment,a SLIM finite element model of the improved and existing structures is established,and the current density distribution,magnetic density distribution in the core,harmonic composition of air gap magnetic density,inherent mechanical characteristic curve,current efficiency and motor normal force of the two structures are analyzed in detail under transient conditions.It shows that compared with the existing structure,the improved type,with a larger current carrying volume,can effectively increase the current intensity and produce a greater electromagnetic thrust.The reverse braking performance and energy consumption braking performance of the improved type and these two factors of the existing structure were compared under different slips.It shows that during the whole process of braking,the improved type can provide greater electromagnetic braking power and improve the performance of the electric brakes on urban rail trains.