Axial Stress Analysis and Comparison of the Novel Dual 3-phase Axial Flux Permanent Magnet Machines

In previous research, a novel three-phase dual-stator axial flux permanent magnet machine characterized by the advantages of compact structure and low moment of inertia is proposed for industrial robot application. In order to improve its functional reliability furtherly, the dual three-phase axial flux permanent magnet machine (DTP-AFPM) is firstly proposed. Benefiting from the combination of 12 slots/10 poles, the coil configuration of one stator disk can be modified to a dual three phase full-pitch winding straightforwardly, as a result, one kind of the DTP-AFPMs is achieved which is named as the no shift model in this paper. For eliminating the coil reconfiguration on each stator disk and the connection of the coils belonging to the same phase between two stator disks, the shift model which is based on the shift of the two stator disks to obtain the phasor difference between two three-phase windings is introduced. The characteristics and electromagnetic performances of these two models are analyzed and compared. However, it should be noted that the light-weight disk-type rotor of DTP-AFPMs also degrade the strength of the rotor. The proposed DTP-AFPMs are more sensitive to the axial stress on the rotor which introduces not only the vibration and noise but also the deformation or even the damage of the rotor. Thus, the axial stress on the rotor is investigated and treated as a critical evaluation indicator. The axial stress is analyzed under both healthy and fault conditions and its distribution on the rotor is given on a 2-D plane.