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By incorporating the merits of fractional-slot concentrated windings and Vernier machine structure, a new multi-pole dual-structure permanent magnet (PM) machine is proposed for low speed, direct-drive applications in this paper. In the outer stator, a fractional-slot concentrated winding is adopted to reduce the slot number and stator yoke height, hence saving space and improving torque density. In the inner stator, a Vernier structure is used to reduce the winding slots, thereby enlarging the slot area to accommodate more conductors, thus the inner stator space is fully utilized. Consequently, the merits of these two structures can be ingeniously integrated into one compact PM machine and the torque density is improved, cogging torque is reduced and the control flexibility with two sets of independent stator windings is increased. By using time-stepping finite element method with curvilinear elements for moving …