Performance Comparison of Stator Slot Permanent Magnet Machines with Non-Overlapping and Overlapping Windings

摘要

In this paper, an overlapping winding (OW) with armature coil pitch of 3 (A3) are applied to 6-slot stator slot permanent magnet machines (SSPM) in order to enhance the torque density and increase the efficiency. The OW layouts are applied to 6-slot SSPMs with different rotor pole numbers. Comparing with the existing SSPMs with non-overlapping winding (NOW), the SSPMs with OW has doubled its fundamental winding factor under the same stator/rotor pole number combination. Thus, the back-EMF and average torque of SSPMs with OW is effectively enhanced. The 6-slot/8-rotor pole (6s8r) SSPMs with A1 and A3 are selected from the candidates with high average torque and their electromagnetic performance is comparatively analyzed with 6s7r-A1 SSPM. It shows that the average torque in 6s8r-A1 SSPM is improved by 114.71% by employing OW at the same copper loss. Although the OW cannot be applied to 6-slot SSPMs with odd rotor poles, the 6s7r-A1 SSPM shows low total harmonic distortion (THD) in back-EMF and significant low torque ripple at on-load condition.