Abstract Recent developments in fuel cell (FC) technologies show great potential to increase flight duration of unmanned aerial vehicles (UAVs) with satisfactory fuel economy. The three most common FCs used to power UAVs are: 1) polymer electrolyte membrane FC, 2) direct methanol FC, and 3) solid oxide FC. Because of the power performance limitation of pure FC propulsion systems, hybrid propulsion systems that integrate FCs with other power sources such as batteries, supercapacitors, solar cells, and conventional internal combustion engines are recommended for UAVs. This paper reviews the current developments in FC hybrid propulsion systems applied to UAVs. The topics covered include the operating principles and characteristics of three typical FCs, issues faced by FC-powered UAVs, specific roles of other electric power sources, pure electric hybrid constructions of FC hybrid propulsion systems, hybrid engine-electric FC hybrid propulsion systems, potential impacts of various flight factors, energy management strategies of FC hybrid propulsion systems, and similarities/differences of FC hybrid propulsion systems in other vehicle applications. Finally, future trends and challenges of FC hybrid propulsion systems are discussed, which could be valuable for the development of next-generation UAVs.

中文翻译：

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燃料电池混合动力推进系统应用于无人机的当前技术与挑战

摘要 燃料电池 (FC) 技术的最新发展显示出增加具有令人满意的燃油经济性的无人驾驶飞行器 (UAV) 飞行时间的巨大潜力。用于为无人机提供动力的三种最常见的 FC 是：1) 聚合物电解质膜 FC，2) 直接甲醇 FC，和 3) 固体氧化物 FC。由于纯燃料电池推进系统的动力性能限制，建议将燃料电池与电池、超级电容器、太阳能电池和传统内燃机等其他动力源集成的混合推进系统用于无人机。本文回顾了应用于无人机的 FC 混合推进系统的当前发展。涵盖的主题包括三种典型燃料电池的工作原理和特性、燃料电池驱动的无人机面临的问题、其他电源的具体作用、FC 混合动力推进系统的纯电动混合结构、混合发动机-电动 FC 混合动力推进系统、各种飞行因素的潜在影响、FC 混合动力推进系统的能量管理策略，以及 FC 混合动力推进系统在其他车辆应用中的异同。最后，讨论了燃料电池混合动力推进系统的未来趋势和挑战，这对下一代无人机的发展可能很有价值。