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Gearless and small motors operating at speeds above 10 000 rpm are finding many applications nowadays. Axial flux permanent magnet (AFPM) motors are compact and lightweight compared to radial flux motors and hence, are considered for various high-speed applications. Eliminating the stator core minimizes the associated high-frequency losses, and hence, coreless AFPM motor can be an option for high-speed applications. Furthermore, the coreless AFPM motor design minimizes the cogging torque and the axial attraction force between the stator core and the rotor magnets. However, the reduction of flux linkage in the stator windings is a challenge in coreless AFPM motor. In this article, the advantages and disadvantages of the printed circuit board (PCB)-based AFPM motor for high-speed, low-power applications are investigated. A detailed performance comparison of the PCB-based coreless AFPM motor and the AFPM motor with the laminated stator core is made. Finite-element analysis is carried out for the electromagnetic, mechanical, and thermal comparison of the two motors and the simulation results are presented. Finally, motor prototypes are fabricated and are tested to ascertain the simulation results. [ABSTRACT FROM AUTHOR]

Axial flux-segmented rotor-switched reluctance motor (SSRM) topology could be a potential candidate for in-wheel electric vehicle application. This topology has the advantage of the increased active surface area for the torque production as compared to the radial flux SSRM for a given volume. To improve the performance of axial flux SSRM (AFSSRM), various stator slot/rotor segment combinations and winding polarities are studied. It is observed that the torque ripple is high for the designed three-phase, 12/8 pole AFSSRM. Therefore, the influence of the stator pole and rotor segment arc angles on the average torque and the torque ripple is studied. In addition, the adjacent rotor segments are displaced with respect to the stator, to reduce the torque dips in the phase commutation region. The proposed arrangement is analyzed using the quasi-3-D finite-element method-based simulation study and it is found that the torque ripple can be reduced by 38%. Furthermore, the low-frequency harmonic content in the torque output is analyzed and compared. The variation of the axial electromagnetic attractive force with displaced rotor segments is discussed. The effectiveness of the proposed technique is verified experimentally. [ABSTRACT FROM PUBLISHER]