Power density improvement of FSCW axial flux permanent magnet motors by designing shape of back yoke

Many studies for axial flux permanent motors(AFPMM) with fractional slot concentrated windings(FSCW) have been researched due to the high torque density. In the case of AFPMM with FSCW, magnetic saturation in the back yoke of stator and rotor sectionally occur in a pattern. But in general, the design of the back yoke is focused on the part that the magnetic saturation mainly occurs. For high torque density, the optimal usage of the amount of core should be considered. So, it is necessary to sort out the part of the core according to the degree of magnetic saturation and adopt an appropriate quantity of core. In this paper, the back yoke of single-sided with 20poles 18slots. AFPMM with FSCW is designed with shape variables to reduce weight or increasing power with equal weight.