Fractional slot permanent magnet machine with outer rotor

This paper deals with the study of fractional slot permanent magnet synchronous machine, under 9 slots/10 poles structure, with outer rotor. It reports some results obtained by means of FEM-based simulation, which have as main goal the improvement of output characteristics. More specific, the inner diameter of the rotor and the stator shoe shape are modified. The analysis takes into consideration both motoring and generating duty and refer mainly to cogging torque and back emf.