Analysis of a Double-Stator Rotary Linear Permanent Magnet Motor with Phase-Group Concentrated-Coil Windings

This paper proposes a double-stator rotary linear permanent magnet motor (DS-RLPMM) with phase-group concentrated-coil (PGCC) windings, which can achieve rotational, linear and helical motions. The rotational driving unit adopts the PGCC windings and spoke-type PM to increase torque density. And an auxiliary stator with a displaced design is incorporated to suppress torque ripple. The linear driving unit utilizes a stator split tooth to reduce thrust ripple. The motor topology, operating principles, and electromagnetic characteristics are introduced. By utilizing single-degree-of-freedom rotational PM motor and linear PM motor as the contrast models, the airgap flux density, back electromotive force, cogging torque, detent force, torque and thrust of these models are predicted by employing the 3-D finite element method. The results demonstrate that the DS-RLPMM exhibits excellent performance in both rotational and linear motions.