Energy management in hybrid energy system for long-duration stratospheric airship mission

In this study, a comprehensive energy-thermal coupling model for stratospheric airships is established to address the dual challenges of energy and buoyancy balance for long-duration missions. A Multi-dimensional Dynamic Programming (MDP) energy management framework is introduced to significantly accelerate the optimization process for hybrid energy system including solar array, battery, and RFC (Regenerative Fuel Cell), achieving 4 % greater maneuverability, 25.42 % less curtailment, and 3.4 % fewer gas loss,. The efficiency of the MDP optimization process is enhanced by the implementation of vectorization and state-to-state traversal with feasibility checks and state reduction, achieving speed improvements of over 1000 times compared to traditional methods. State variables and time steps are appropriately discretized to balance feasible search regions and control resolution. The global search capability of the MDP algorithm allows for stable power consumption and distribution, resulting in lower curtailment rates and higher maneuverability. Additionally, a 10.9 % increase in endurance to 1301h and 1835 km h cumulative boundary exceedance decrease, obtained by hierarchical online energy management, are achieved by extracting rules from deterministic global algorithms, incorporating energy consumption prediction, energy harvesting prediction, residency prediction, temperature following, and RFC power stabilization.