A Double-layer Fluc-Concentrating Permanent Magnet In-wheel Motor for Special Electric Vehicle

In this paper, a double-layer interior permanent magnet (IPM) motor with fractional slot distribution winding is presented for special electric vehicles (EVs) to achieve high torque density and high air-gap flux density. Firstly, the flux-concentrating mechanism is revealed based on the magnetic equivalent circuit (MEC) model. Then, the contribution of air-gap flux density with different flux paths is obtained based on the finite element method (FEM). In addition, the electromagnetic performance of the proposed motor is obtained, and compared with traditional V-shape IPM motor, including air-gap flux density, back electromotive force (back-EMF), cogging torque, and torque characteristic. The results show that the proposed IPM motor has a higher torque density than the traditional V-shape IPM motor. Finally, a 54-slot/l2-pole PM motor is manufactured and tested to verify its performance.