Ironless stator axial-flux permanent magnet (AFPM) machines provide many attractive electromagnetic performances such as high efficiency in high-frequency mode and strong short-term overload ability, which make them more competitive in flywheel energy storage applications. However, designing high-torque-density AFPM machines, particularly their ironless stators, is with significant challenges and needs great efforts. In this article, a high-strength oil-immersed cooling stator with nonoverlapping concentrated winding is proposed for high-power ironless stator AFPM machine applications. This article explains in detail the design, analysis, and manufacturing process of the proposed oil-immersed cooling stator. With the three-dimensional finite-element analysis (3-D FEA), a 9000-r/m/50-kW 12-slot/10-pole prototype for a flywheel energy storage system is successfully designed and developed using the proposed high-strength oil-immersed cooling ironless stator. The experimental test results demonstrate the effectiveness of the cooling design and mechanical strength.

中文翻译：

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大功率无铁芯AFPM电机非重叠集中绕组油浸式冷却定子的设计与分析

无铁芯定子轴向磁通永磁 (AFPM) 电机提供许多有吸引力的电磁性能，例如高频模式下的高效率和强大的短期过载能力，使其在飞轮储能应用中更具竞争力。然而，设计高扭矩密度 AFPM 机器，特别是它们的无铁芯定子，面临着巨大的挑战，需要付出巨大的努力。在本文中，针对大功率无铁心定子 AFPM 电机应用提出了一种具有非重叠集中绕组的高强度油浸冷却定子。本文详细解释了所提出的油浸冷却定子的设计、分析和制造过程。通过三维有限元分析（3-D FEA），9000-r/m/50-kW 12-slot/10-pole 飞轮储能系统原型使用所提出的高强度油浸冷却无铁芯定子成功设计和开发。实验测试结果证明了冷却设计和机械强度的有效性。