This paper proposes a new dual slot permanent magnet (PM) machine with complementary rotors. The novelty lies in the use of complementary rotors, which are two salient pole rotors mechanically staggered by 180 electrical degrees. This design can reduce leakage flux and increase torque density. The stator is sandwiched between the two rotors and PM excitations are employed on both sides of the stator slots. All the PMs are circumferentially magnetized, and the magnetizing directions are the same for PMs in the same slot while opposite for PMs in adjacent slots. The two rotors are fixed at the end part, so they have the same rotating speed and the proposed machine only has one mechanical port. Concentrated windings are wound on the stator teeth, and the flux linked with each phase changes when the complementary rotors rotate, inducing electromotive force (EMF). The PMs on both sides of the slots can contribute to electromagnetic torque generation, so the proposed machine can be designed with larger torque. Meanwhile, since the flux paths of PMs and armature current are parallel, the PMs do not suffer from demagnetization risk. The electromagnetic performance of the proposed machine is investigated in detail using the finite element method.
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