Comparison of variable flux reluctance, switched flux and fractional slot PM12-stator slots machines having 10- and 14-rotor poles

In this paper, the electromagnetic performance of variable flux reluctance machines (VFRMs), switched flux permanent magnet machines (SFPMMs), and fractional slot permanent magnet machines (FSPMMs) are investigated and compared together with the interior permanent magnet machine (IPM) used in Toyota/Prius-2010. All the machines having the stator/rotor pole combinations of 12/10 and 12/14 are optimized by the global optimization with genetic algorithm (GA) under the restriction of same outer diameter, stack length and air-gap, which are the same as those of Prius-IPM machine. It shows that the torque densities of SFPMMs and FSPMMs are similar and higher than the non-PM VFRMs. However, in terms of robust and cost, the VFRMs can exhibit better performance over the other PM machines.