Design and Control of a Novel Yokeless Axial Flux-Switching Permanent-Magnet Motor

In this paper, in order to increase the space for windings and torque capability, a novel yokeless and segmented armature axial field flux-switching sandwiched permanent-magnet (YASA-AFFSSPM) motor which is appropriate for direct-drive applications is proposed. The proposed motor is composed of single stator and two rotors. Stator winding has unit displacement winding factor. Moreover, two rotors are displaced by π (elec.) shift. The unaligned rotors are employed to achieve yokeless and segmented armature structure and also reduce the cogging torque. A three-phase 12/19-pole YASA-AFFSSPM motor is designed. This proposed motor and conventional AFFSSPM are optimized and compared with the conventional AFFSPM. It is shown that the YASA-AFFSSPM motor exhibits higher torque density and greatly lower cogging torque. To evaluate the static and dynamic performance of the YASA-AFFSSPM motor, the sensor-less control drives have been applied. A prototype of the optimized YASA-AFFSSPM motor is manufactured and tested.