A Novel Multi-Excitation-Tooth Nonoverlapping Stator Wound Field Synchronous Machine With Salient Rotor

In this paper, based on the conventional nonoverlapping stator wound field synchronous (N-SWFS) machine, a novel multi-excitation-tooth N-SWFS (MN-SWFS) machine is firstly proposed by changing winding configurations and the excitation-teeth shape. The electromagnetic performance of four optimized MN-SWFS machines sharing the same 12-stator-teeth but different rotor-teeth numbers, namely 12/10, 12/11, 12/13, and 12/14, is compared by finite element analysis (FEA). The corresponding simulation results show that 12/10 and 12/14 are the optimal stator-teeth/rotor-teeth combinations due to much smaller back electromotive force (back-EMF) THD and torque ripple ( $T_{rip}$ ). Finally, a series of comparative studies are carried out on the proposed MN-SWFS machines and the conventional N-SWFS machines. The comparative results validate that the proposed 12/10 and 12/14 MN-SWFS machines exhibit better electromagnetic performance than the conventional 12/11 and 12/13 N-SWFS machines, such as higher fundamental back-EMF amplitude and greater torque output capability, though their cogging torque ( $T_{cog}$ ) and torque ripple are slightly higher, and the torque anti-saturation ability is slightly weaker.