Optimal power management and sizing of a fuel cell electric UAV

Abstract

This paper puts forth a new approach for reducing the weight of a fuel cell (FC) powered fixed-wing unmanned aerial vehicle (UAV). The key innovation combines concurrent optimization of the FC and battery sizes along with their power management strategy. A particle swarm optimization (PSO) algorithm is leveraged to perform this concurrent optimization. Through these optimizations, reductions in weight are achieved for both the power sources and fuel tank, while maintaining optimized power output profiles. The optimization results demonstrate significant system weight reductions of 66.87% and 47.72%, for two distinct power profiles that were analyzed. Profile I corresponds to a smooth, continuous power demand over time, while Profile II is a fluctuant profile. In addition to weight savings, the power management optimization reveals an important interplay between the power profile demanded, control strategy, and sizing of the power sources. It was found that the FC is best sized to match the longest duration high power segment of the mission. This power-matched sizing results in stable, efficient operation of the FC over time. Conversely, the battery is sized sufficiently large to meet peak instantaneous power demands that exceed the FC capability. These findings showcase the potential of the proposed optimization approach to facilitate improved performance for electric fixed-wing UAVs. Moving forward, a series of numerical simulations validate the proposed methodology and confirm the deduced results.