【目的】系留式大载荷灭火无人机在200 m高空长时悬停场景下面临动力系统功率密度不足、绕组温升及百小时级可靠性欠缺的严峻挑战。本研究针对传统外转子永磁同步电机因圆线绕组铜耗大、平行充磁气隙磁密低导致的性能瓶颈，提出融合多物理场协同优化与创新拓扑设计的系统性解决方案，旨在满足高空消防任务对电推进系统轻量化、低热耗与高环境适应性的三重严苛需求。【方法】基于多参数敏感度分级降解模型，采用响应面法对36槽32极外转子电机开展多参数耦合优化。通过引入五段Halbach永磁阵列拓扑提升气隙磁密基波幅值并抑制转矩脉动，结合扁线绕组端部拓扑优化与燕尾槽定子设计将槽满率提高至78%，显著降低交流铜耗。利用遗传算法筛选综合目标函数的Pareto最优解，完成样机制作，并构建螺旋桨台架测试系统与200 m整机飞行验证平台。【结果】优化后电机功率密度达3.73 kW/kg，系统额定工况效率为92.9%；额定螺旋桨负载下绕组温升118 K；200 m高空飞行测试中电驱动系统运行稳定；100 h持续飞行后效率衰减小于0.1%，优于同类产品。【结论】本研究提出的分级优化框架与Halbach-扁线绕组技术协同方案，显著提升了系留无人机动力系统的功率密度与运行可靠性，为高空长时悬停作业场景提供了经飞行验证的优选技术路径。

[Objective] Tethered heavy-payload firefighting UAVs performing sustained hovering at 200 m altitude face critical challenges: Insufficient power density, excessive winding temperature rise, and inadequate 100-hour operational reliability. Addressing performance limitations in conventional external-rotor permanent magnet synchronous motor-specifically high AC copper losses from round-wire windings and low air-gap flux density due to parallel magnetization, this study proposes an integrated solution combining multiphysics collaborative optimization with innovative topological design. The approach targets stringent triple requirements for electric propulsion systems: lightweight construction, minimized heat dissipation, and superior operational robustness in aerial firefighting scenarios. [Methods] Using a multi-parameter sensitivity hierarchical degradation model validated for predictive accuracy, parameter co-optimization for an external-rotor motor with 36 slot/32 pole was performed via response surface methodology. The design incorporated a five-segment Halbach magnet array topology to enhance fundamental air-gap flux density while suppressing torque ripple through optimized magnetization angle distribution. This was combined with flat-wire winding technology and a dovetail-groove stator design, achieving a 78% slot fill factor and reducing AC copper losses via three-dimensional end-turn optimization. Pareto-optimal solutions balancing thermal stability and efficiency were selected using a genetic algorithm based on a composite objective function. Prototypes underwent rigorous validation through propeller dynamometer tests simulating full-load aerodynamic profiles and flight demonstrations at 200 m altitude under variable atmospheric conditions. [Results] The optimized motor achieved a power density of 3.73 kW/kg with 92.9% system efficiency under rated propeller load. Winding temperature rise stabilized at 118 K, the electric drive system operated stably during the 200 m altitude flight test. Following 100 hours of continuous flight, efficiency degradation remained below 0.1%, outperforming similar products. [Conclusion] The hierarchical optimization framework synergized with Halbach-flat wire winding technology, achieving unprecedented power density and operational reliability essential for prolonged firefighting missions, while offering a scalable methodology for high-altitude electric propulsion design.

国家重点研发计划项目(2022YFC3090500);国家自然科学基金(U24A20145)