The Formula SAE Electric Vehicle Competition: A High-Torque Density Permanent Magnet Motor

The formula sae, or formula student, is an international vehicle design competition carried out by university students. This article deals with a fractional-slot synchronous permanent magnet (PM) machine designed to be mounted in the wheel hub of an electric vehicle (EV). By adopting an outer ironless rotor topology, a Halbach array magnet structure, and light materials, a low rotor inertia and a high-torque density are achieved. The results described in this article provide a quantitative assessment of the achievable torque density for small motors.