Design and Evaluation of Axial-Flux Permanent Magnet Machine with Enhanced Saliency

Axial flux permanent magnet synchronous machines (AF-PMSMs) are used in applications that require high power and torque densities like electrical vehicles. In such operation scenarios, a wide constant power speed range is crucial, but most PM machine designs lack this capability since they have low saliency. This paper proposes the design of an AF-PMSM with enhanced saliency, providing promising torque ratings. A 6-pole 36-slot spoke-type permanent magnet machine with a special rotor structure was designed and evaluated by means of threedimensional finite element analysis. Results show that the proposed design can provide a high overall torque due to the contribution of both magnets and reluctance components, also delivering considerable saliency ratings. This can enable the machine to operate in a wide speed range for electrical or hybrid vehicle in-wheel applications.