Comparison of optimal slot/pole number combinations in fractional slot permanent magnet synchronous machines having similar slot and pole numbers

Abstract

Here, the selection of optimal slot/pole (Ns-slot/pr-pole) number combination between the pairs of fractional slot concentrated winding (FSCW) permanent magnet synchronous machines (PMSMs) with Ns = 2pr ± 1 or Ns = 2pr ± 2 will be analysed by a modified winding function accounting for slot opening and validated by finite element method. The results show that for FSCW PMSMs with Ns = 2pr ± 1 or Ns = 2pr ± 2, the higher pole machine will have larger winding factor and hence better torque performance than the lower pole one. Moreover, it also reveals that this torque advantage is more evident in the external rotor machine than that in internal rotor machine.

Keywords

• synchronous machines
• rotors
• permanent magnets
• permanent magnet machines
• permanent magnet motors
• finite element analysis
• torque
• machine windings
• (FSCW) permanent magnet synchronous machines
• slot opening
• Ns-slot/pr-pole
• pole numbers
• similar slot
• fractional slot permanent magnet synchronous machines
• optimal slot/pole number combination
• lower pole
• higher pole machine