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.

中文翻译：

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SAE 电动汽车方程式大赛：高扭矩密度永磁电机

方程式赛，或方程式学生，是由大学生开展的国际车辆设计比赛。本文介绍了一种设计用于安装在电动汽车 (EV) 轮毂中的分数槽同步永磁 (PM) 电机。采用外转子无铁芯拓扑结构，海尔贝克阵列磁体结构，材料轻，转子惯性小，扭矩密度高。本文中描述的结果提供了对小型电机可实现的扭矩密度的定量评估。