A new primary permanent magnet linear motor for urban rail transit

In this paper, a new permanent magnet (PM) linear motor is proposed, in which both the magnets and armature windings are placed in the short mover, while the long stator consists of iron core only. Hence, this new PM linear motor can be called as primary permanent magnet linear motor, which exhibits the advantages of robust and simple mover, low cost, high efficiency, high power factor, and high thrust force density, especially suitable for the long stator application such as urban rail transit. Its topology structure and operation principle are introduced firstly. Then, the static characteristics are investigated, including field distributions, flux-linkage, back-EMF, phase inductance and thrust force. In addition, the technique of skewing stator teeth is adopted to improve the electromagnetic performance. Finally, finite element method (FEM) is used to verify the theoretical analysis results.