Novel 24-slots14-poles fractional-slot concentrated winding topology with low-space harmonics for electrical machine

Abstract

This paper proposes a novel winding layout for the electric machines with fractional-slot concentrated windings (FSCW) using a stator shifting concept, with which all the non-working harmonics can be completely cancelled or significantly reduced and the non-overlapping winding can be kept. First, the basic winding layout with a 24-slot 14-pole machine to reduce the significant 1st sub-harmonic will be presented for machines with single-layer (SL) windings. From this, a novel double layer (DL) winding layout using the stator-shifting concept will be introduced. By adopting two SL winding sets with a 105° mechanical angle shift with respect to each other, it is not necessary to use overlapping windings. With this configuration, the 1st sub-harmonic will be completely cancelled and the parasitic 5th harmonic will be significantly reduced. Hence, the rotor losses, specifically magnet loss will be significantly reduced. Finally, two PM machines with different DL winding layout, namely, conventional 12-slot 14-pole and 24-slot 14-pole machine, will be designed and compared to validate the advantages of this winding topology.

Keywords

• permanent magnet machines
• eddy current losses
• rotors
• torque
• machine windings
• synchronous machines
• stators
• finite element analysis
• novel 24-slots14-poles fractional-slot
• winding topology
• low-space harmonics
• electrical machine
• novel winding layout
• fractional-slot concentrated windings
• stator shifting concept
• nonoverlapping windings
• basic winding layout
• 24-slot 14-pole machine
• single-layer windings
• stator-shifting concept
• SL winding sets
• 105° mechanical angle shift
• overlapping windings
• parasitic 5th harmonic
• PM machines
• different DL winding layout
• 12-slot 14-pole