Analysis of Propulsion and Attraction Characteristic of Double Secondary Permanent Magnet Linear Synchronous Motor for Maglev Train

In order to accelerate the maglev train to the high or ultra-high speed range, a double-secondary permanent magnet linear synchronous motor (DS-PMLSM) with N-S configuration is proposed which has the merits of high thrust and high power density. The two secondaries of the motor share a long primary and the armature is ironless. In this paper, a layered model of DS-PMLSM is established, and the expressions of the air gap magnetic density and propulsion in Fourier form are derived. A virtual N-N configuration motor compensation method is proposed in order to reflect the longitudinal end effect of the secondaries. The expression of the attraction between the two secondaries is derived based on the equivalent surface current method. Finally, the consistency and correctness of the analytical derivation are verified by the finite element (FEM) simulation. The analytical derivations in this paper provide the theoretical support for the design of the motor structure parameters.