Design and Analysis of Fractional-slot Concentrated Winding PMSMs with Unequal Tooth Towards Improving Torque Density

The high torque density permanent magnet synchronous motors (PMSMs) are desired in a wide range of applications today. Adopting the unequal tooth structure represents an effective method to enhance the torque density of PMSMs, However, the current research on unequal tooth is focused on single-layer windings. This article analyzed and revealed the imbalanced distribution of flux linkage in a fractional slot PMSM with 24-slots and 22-poles. Additionally, the article discusses the causes of the observed imbalance in the current flux linkage within each coil. Therefore proposed an unequal tooth structure to increase the torque density.