Conceptual design and energy management strategy for UAV with hybrid solar and hydrogen energy

According to the long-endurance demand of small low-altitude electric UAVs, a hybrid solar and hydrogen energy system and a configuration of long-endurance small low-altitude UAV is introduced. Based on the typical flight profile and the characteristics of solar cells and fuel cells, a conceptual design method which considers the coupling relationship of weight and energy and the corresponding profile-driven energy management strategy is proposed. Energy system models are built. Furthermore, an energy control procedure is provided, and a simulation platform for hybrid energy management is developed. For an instance, a configuration scheme of the UAV with 1.5 kg payload is achieved. Based on this case, the influences of the characteristics of the energy sources on the flight results are analyzed in the process of simulation. Results prove that the strategy of energy management is able to achieve an efficient power distribution in accordance with the flight profile as well as satisfies the power requirements of all stages. The endurance of the UAV reaches 21 h on winter solstice and a whole day and whole night on summer solstice. Under the same weight of energy systems, the endurance of the proposed hybrid-powered UAV is 5.5 times of the lithium battery powered UAV and 1.2 times of solar powered UAV, respectively.