Analysis of a six- and three-phase interior permanent magnet synchronous machine with flux concentration for an electrical bike

This paper presents a comparison between an interior permanent magnet synchronous machine (IPMSM) with two different windings. The two windings subject to this analysis are concentrated six- and concentrated three-phase windings. The focus is put on concentrated windings, because by using this type of winding production costs can be kept low. The mentioned IPMSM is designed for the use in an electrical bike (E-Bike), the size of which is therefore limited by the frame of the bike. This leads to just a few possible combinations in the numbers of slots and poles of the machine. Concentrated six-phase windings have the possibility to reach higher values in the winding factors than three-phase windings of the same machine. The assumption that the six-phase winding generates more torque and reaches a higher efficiency than the three-phase winding is tested in a finite element simulation. The results of this simulation have shown that there can be an increase of the torque production of up to 2% and a better efficiency of 0.4% with concentrated six-phase windings with a BLDC commutated current.