A Comprehensive Analysis of a Complementary-Rotor Doubly Salient Permanent Magnet Motor for High Torque Applications

This paper introduces a new single slot yokeless permanent magnet (PM) motor with rotor complementary structure. This structure is also a kind of enhanced doubly salient PM motor which has improved output torque and also reduced unbalanced magnetic force. There are two salient rotors, shifted 180 electrical degrees. This design also helps to reduce the leakage flux. Slot PMs are circumferentially magnetized and radial pairs of PMs have the same direction. But the direction of adjacent slot PMs pairs are opposite. The stator is located between two rotors and PM excitations are on both the outer and inner sides of the stator. Both rotors are mechanically coupled together and rotate at the same speed. Concentrated windings are wrapped around the stator teeth and the flux path is switched between two rotors depending on which rotor aligns with the stator teeth. The risk of PM demagnetization has been also reduced because the flux path of armature and PM excitation are parallel. The performance characteristic of this improved doubly salient PM motor (DSPM) is verified using a finite element method (FEM).