Advanced improvement of single layer tooth coil windings by systematic adaption of the tooth width

Abstract Concentrated windings offer advantages over distributed windings, such as a smaller end winding length and simplified production. At the same time, this winding has the disadvantage of a high harmonic content in the stator field. This paper deals with the optimization of PMSM with single layer tooth coil windings. It is investigated how the harmonic spectrum of the current sheet can be optimized by adjusting the tooth width. The influence on the pitch factors of the individual orders is derived. Using an example winding, the tooth width is systematically varied and it is shown that the adjustment has different effects on the orders. This enables increasing the torque forming order of the current sheet while reducing the disturbing orders. The influence of tooth width on torque is determined using an FEM simulation. It is proven that this adjustment can increase the mean torque while significantly reducing torque ripple. Additionally, the cogging torque can also be reduced. With an adapted tooth width, other numbers of pole pairs and other pole arc ratios may be suitable compared with a uniform tooth width. Therefore, this paper presents and compares various configurations with different pole arc ratios and tooth widths to demonstrate the optimization potential.