Study on a Long Primary Flux-Switching Permanent Magnet Linear Motor for Electromagnetic Launch Systems

Based on the principle of rotational flux-switching permanent magnet machines, a novel double-sided long primary flux-switching permanent magnet linear motor (FSPMLM) is proposed for electromagnetic launch systems (EMLS). Compared with traditional induction and synchronous linear machines used in EMLS, the proposed motor is more suitable for EMLS because of its high thrust density and simple structure of the secondary. First, the structure and operation principle of the proposed FSPMLM are given and analyzed. Second, considering the longitudinal end effect, the thrust components are analyzed and derived. According to the generation principle of the thrust components, the optimal methods, implemented to reduce the thrust ripple, are obtained and analyzed. In addition, a 2-D transient finite element method is used to investigate the dynamic electromagnetic characteristics of the FSPMLM and the process of electromagnetic launch. Finally, a prototype of single-sided FSPMLM is employed to validate the thrust performance of the proposed machine.