3-D Finite element method analysis of twin-armature permanent magnet motor with two degrees of mechanical freedom

Abstract

In this paper, the authors present a twin-armature rotary-linear permanent magnet (PM) motor. The stator consists of two armatures which generate two rotating magnetic fields and the rotor consists of two rigidly coupled parts. Each part consists of PMs on its surface which are skewed in opposite directions. By changing the direction of magnetic field rotation in each armature, the resultant force produced by the motor can be varied between rotary, linear, or rotary-linear. The torque and axial forces acting on the rotor are calculated by using 3-D finite element method analysis. The influence of the PM skew angle on the torque and linear force exerted on the rotor is investigated and presented. The effect of cogging torque and torque ripple reduction for the twin-armature rotary-linear PM motor is also discussed