Study the Influence of Edge Points of Magnet Surface and Stator Core on the Cogging Torque Reduction in Permanent Magnet Machine

Abstract

Cogging torque in permanent magnet machine application effects to some undesirable vibration and noises. To minimize the cogging torque in permanent magnet machine's the most important issue recently. Influence the number of edge points in the magnet of one and two steps of magnet edge slotting was studied in this paper'. For purpose of study, the structure of permanent magnet machine with 18 slot / 8 pole has been chosen, and the magnetic flux of all magnets was radial. The finite element of 2D based on FEMM 4.2 software was implemented to analysis the magnet flux distribution in air gap. Simulation results showed that by improvement of edge point at magnet edge of the two steps of slotting in magnet edge could reduce the cogging torque of permanent magnet significantly when compared with the initial structure. Employing the numerical simulation, both of the machine structures were analysed. It has been found that, the cogging torque reduction of edge points with 8 points has the highest reduction around 98.84 % compared with initial structure of the permanent magnet machine.