Design analysis of slit stator motors

A design method of stator core structures is proposed to modify the component ratio of space harmonics in the magnetic field due to stator windings for torque enhancement and efficiency improvement. In fractional-slot concentrated winding configurations, the magnetic field due to the stator windings includes a specific space harmonic to be increased for drive torque and other dominant space harmonic to be reduced. In the proposed design, slit-like flux barriers are located in wound teeth for a 12-slot 10-pole machine. The stator slitting increases the driving space harmonic and reduces the other dominant space harmonic. The efficacy of this method is determined by deriving the winding factor and estimating the magnetic flux distribution and the motor performance through a finite-element method analysis.