Comparison of Performance Characteristics of Axial-Flux Permanent-Magnet Synchronous Machine With Different Magnet Shapes

To compete with other types of electrical machines as well as other manufacturers, the performance characteristics of axial-flux permanent-magnet (AFPM) machines should be improved. Reduction of the higher harmonic components from the induced back electromotive force is preferred during design process of an electrical machine. To achieve an almost sinusoidal induced phase voltage, a sinusoidal air-gap flux density distribution should be produced. Furthermore, in order to easy startup and also less noisy performance of electrical machines, the cogging torque of the machine should be reduced. In this paper, the surface-mounted AFPM machines equipped with magnets with different outlines are investigated and the machine performances are computed via 3-D finite-element analysis. According to the obtained results, magnets with sinusoidal outline offer better performance characteristics compared with cylindrical and sector-like magnets.