End-effects analysis and experimental study of a double stator linear-rotary permanent magnet motor with long mover

A double stator linear-rotary permanent magnet motor, which has a long tuber ferromagnetic mover core with permanent magnets (PMs) arranged on its inner and outer surfaces, is proposed for two degree of freedom drive in this study. Due to the topology of the long tuber mover, the end-effects, including the interaction between the outer stator end and the mover, the effects of the inner PM length, and the interaction between the inner stator end and the mover, are presented and analysed. Based on the three-dimensional (3D) finite-element method, the influences of the end-effects on the electromagnetic characteristics, such as the flux distributions, flux density, electromagnetic force and torque, and output power, are investigated. Meanwhile, the topology with the minimised end-effects is given, and a prototype is built. The dynamic performances of the prototype are tested via a specific experimental platform. The results are in agreement with that of the 3D finite-element analysis.