Design of a multiphase coreless axial flux permanent magnet machine for unmanned aerial vehicle propulsion

This work investigates the design of a multiphase coreless axial flux permanent magnet machine with concentrated windings, for the propulsion of an unmanned aerial vehicle. Such a system requires very high power and torque densities, which tend to be in contrast with other important requirements such as high efficiency and resilience. In order to simplify the design of the machine, an original method for the selection of the poles to coils ratio is proposed. The paper then presents a 3D finite element analysis based refinement for the final design; finally, a full scale prototype has been built and a preliminary no load test is reported.