An improved energy management strategy of hybrid photovoltaic/battery/fuel cell system for stratospheric airship

Energy management system is very critical for solving the energy problem of a long endurance stratospheric airship. But the researches about the energy management system and energy management strategy for a stratospheric airship are rare. This paper presents the hybrid energy system consisting of one renewable energy system and two energy storage systems. Combined with the models of energy harvesting, balance and storage, and the thermal model of the PV (Photovoltaic) panel, the details of the rule-based energy management strategy to cooperate the three energy sources or storage devices: photovoltaic, lithium battery and fuel cell are obtained. Furthermore, the energy management strategy in the situation of a storage system failure is proposed to ensure the operation of the airborne equipment. In the course of the investigation, the power curves and the state of charge of the energy storage systems are reported in detail to prove the validity and applicability of the management strategies. It indicates that the energy system of the airship can provide uninterrupted energy to control system and payload system, but can not resist the wind drag after LB failure, which will increase the difficulty of the trajectory planning. The results indicate that the strategy is helpful for planning energy management.