Fractional-slot low speed large torque permanent magnet brushless motors

In order to study the performance of the fractional-slot low speed large torque permanent magnet brushless motor (PMBM), all the potential three-phase 10-pole PMBMs, which have the different slot number per pole per phase (q) of equal to or less than unit, but the same main dimensions, electromagnetic parameters and rated ones, are valuated comparatively. The inductance, no-load air-gap induced EMF, slot torque ripple and armature MMF harmonics for all the motors are exhibited especially which determine their different characteristics to some extent. At last, a prototyped 10-pole 12-slot single-layer-winding motor is adopted to verify the analysis successfully.