Electromagnetic analysis of double-sided axial flux permanent magnet motor with ring-wound type slotless stator based on analytical modeling

This paper deals with electromagnetic analysis of double-sided axial flux permanent magnet (AFPM) motor with ring-wound type slotless (RWS) stator. On the basis of magnetic vector potential and polar-coordinate system, the magnetic field solutions due to PM rotor are obtained. In particular, 3-D problem, that is, the reduction of magnetic fields near outer and inner radius of the PM is solved by introducing a special function for radial position. And then, analytical solutions for torque and back-emf are also derived. The predictions are shown in good agreement with those obtained from 3-D finite element (FE) analyses. Finally, based on derived characteristic equations, performance comparison of AFPM motors with concentrated and distributed windings is carried out.