Effect of Combining of Shaping at Magnet Edge and Dummy Slotting at Stator Core on the Cogging Torque Reduction in Permanent Magnet Generator

Abstract

Effect of combining the shaping at magnet edge and dummy slotting at stator on the cogging torque reduction in permanent magnet generator was studied. The cogging torque is the most issues in permanent magnet generator application, since it effects to reduce the generator performance. A permanent magnet generator with 24 slots and 20 poles structure is presented. For purpose of study, in the beginning the permanent magnet generator with conventional structure has been investigated as the basic reference of initial structure. In order to improve the performance of the permanent magnet generator, the magnet edge was shaped but the stator core is kept remain conventional structure. It can be found that the magnet edge effects to inprove a little bit of the performance of the permanent magnet generator. In the next investigation, the magnet edge slotting and dummy slotting in stator core of the permanent magnet generator was combined. Using the FEMM 4.2, the cogging torque value of the proposed of permanent magnet generator were analysed and compared. It was found that cogging torque reduction of the permanent magnet generator with combining the dummy slotting at stator core and magnet edge shaping can reduce the cogging torque from 0.0028554 N.m (intial base line) to 0.0000165 N.m (proposed model). In other word, the cogging torque can be to around 99.42 % compared with the base line. The magnet flux density at core of the permanent magnet generator proposed can be reduced to 35 %.