A new axial flux permanent magnet Segmented-Armature-Torus machine for in-wheel direct drive applications

A novel axial flux permanent magnet (AFPM) machine with a segmented-armature torus (SAT) topology is investigated. The machine's key feature rests on a new and simple configuration of laminated stator poles, which allows high flux density similar to that of the radial flux machines to be established. A full analytical model of the proposed AFPM machine is first developed. To overcome the analytical complexity arising from the novel stator configuration, an efficient and yet realistic approximation is used. Then a three-dimensional (3-D) finite element analysis (FEA) model of a 6 kW AFPM machine is developed for the validation of the analytical model. Finally, experimental results are obtained from an AFPM prototype motor, which has been designed by the sizing equations developed in the analytical model. The results from the analytical model are then compared with those from the FEA model and the tests of the prototype motor. The validity of the analytical model and the viability of the proposed AFPM machine as a leading contender for in-wheel direct drive traction applications are then confirmed.