A Novel Secondary Structure to Research on Dynamic Longitudinal Edge Effect of a Short-Primary HTS Linear Induction Motor for Subway Transportation
In this paper, a novel secondary structure has been proposed to analyze the dynamic longitudinal edge effect (DLEE) of high temperature superconducting (HTS) linear induction motor (LIM). Taking a 3.5 kW short-primary HTS LIM for example, the back iron of secondary plate was cut into various numeral pieces to verify the validity of the model for reducing the influence of the DLEE. According to the basic principle and electromagnetic field theory, the flux density distributions, the electromagnetic thrust, and the harmonic analysis of an effective three-dimensional (3-D) analysis model were implemented by 3-D finite element method in different configurations and parameters. The optimal numeral pieces of back iron were presented. A useful conclusion has been drawn that, with the construction of the novel secondary back iron, influence of the DLEE could be reduced greatly. It provides a good way for optimizing the motor structure and industrial application in subway transportation.