Designing and Prototyping an Axial-Flux Machine Using Ferrite PM and Round Wire for Traction Applications: Comparison With a Radial-Flux Machine Using Nd-Fe-B PM and Rectangular Wire

This paper proposes a novel axial-flux permanent magnet machine (AFPM) employing ferrite permanent magnets (PMs) and round copper wire. The proposed AFPM adopts a novel rotor structure and uses tooth-tips with a suitable trapezoidal shape. These structures compensate for the low magnetomotive force of the round copper wire and ferrite PMs, achieving high performance at low cost. Additionally, compared with an off-the-shelf radial-flux permanent magnet machine (RFPM) using Nd-sintered PMs and rectangular copper wire, the proposed AFPM achieves the same output power and higher efficiency, despite using ferrite PMs and the round copper wire. Finally, a prototype of the proposed AFPM was manufactured and evaluated experimentally. The prototype achieved a high efficiency of over 95% across a wide operating area while maintaining required maximum torque, suggesting its potential for traction applications.