A New Technique to Reduce the Cogging Torque of Integral Slot Number in Permanent Magnet Synchronous Machine

Abstract

This paper proposed a new cogging torque reduction technique of integral slot number in the permanent magnet synchronous machine (PMSM). The purpose of the proposed new technique simulated on the PMSM with 48 slot/6 pole structure. In the study, the magnet edge of the PMSM was slotted to minimize the cogging torque while the stator core has remained natural. Slotting in magnet edge is one of the techniques to reduce the cogging torque in PMSMs, which has been existed in the previous research. In the proposed structure, we employed the two steps of slotting in magnets edge as one of the cogging torque reduction techniques. In this paper, authors have investigated three permanent magnet synchronous machine with different magnet structure has been studied and compared. The proposed permanent magnet synchronous machine with employed two steps of slotting has shown to promise the best of cogging torque reduction. The performance of the permanent magnet synchronous machine studied has been computed and analyzed by finite element analysis. It is found that the smaller cross-section area of magnet pole results in the decrement of cogging torque and air gap normal flux density in the PMSM. The new slotting in the magnet edge reduces the magnet pole cross-section and the cogging torque. The cogging torque of the proposed structure could be reduced around 98.8 % compared with the initial structure. The two steps of slotting could reduce the cogging torque of integral slot number in permanent magnet synchronous machine significantly.