Influence of edge slotting of magnet pole with fixed slot opening width on the cogging torque in inset permanent magnet synchronous machine

The cogging torque in an inset permanent magnet synchronous machine causes some undesirable vibration and noises which should be reduced in the earliest possible stage of design. The influences of edge slotting and slot opening width in the magnet rotor pole on the cogging torque were investigated in this article. The structure of the proposed inset permanent magnet synchronous machine has 8 poles and 24 stator slots with fixed slot opening width and a modified magnet pole in the rotor. The finite element method magnetics (FEMM 4.2) tool was used to investigate the core saturation induced in the stator and rotor of the inset permanent magnet synchronous machine. The simulation results show that the slotting design in the magnet edge can effectively reduce the cogging torque of the inset permanent magnet synchronous machine.