High Torque Density Fractional-Slot Concentrated-Winding Axial-Flux Permanent-Magnet Machine with Modular SMC Stator

Abstract

In this paper the design and implementation of a single-stator double-rotor fractional-slot concentrated-winding (FSCW) axial-flux permanent-magnet (AFPM) machine with modular Soft magnetic composites (SMC)stator and oil immersed forced cooling are presented. Shorter end-winding length and higher fill factor with rectangular copper wire can be realized by employing the yokeless and segmented stator. A fully sealed stator with oil-immersed cooling is proposed to enable a 20A/mm2 current density in the armature windings for stable operation. Meanwhile, the robustness of stator and rotor are taken into account due to the stator modularity weakening effect on strength. The FEA is used to validate the electromagnetic and mechanical performance. The construction and experimental verification of a full-scale 30kW prototype are elaborated to verify the predicted performances in terms of torque, efficiency and cooling.