Fractional-Slot Concentrated-Winding Axial-Flux Permanent-Magnet Machine With Tooth-Wound Coils

This paper presents the design, the finite element analysis validation of a double-stator single-rotor fractional-slot concentrated-winding axial-flux permanent magnet machine with tooth-wound coils. In this particular topology, the flux travels axially through the permanent magnets, from one stator to the opposite, so that there is no need for any rotor back-iron. In order to guarantee sufficient mechanical stiffness of the rotor, the support of the permanent magnets is made of stainless steel. Three different variants of this support are proposed, with the aim of minimizing the induced losses therein. Machine performances both at no load and at rated load are analyzed by using time-stepped 2D FEA and losses in the rotor are compared for the different support variants. A full scale prototype has been built and preliminary experimental results are given.