Mission-Oriented Design and Optimization of a Hybrid Fuel Cell-Battery System for Unmanned Aerial Vehicles

Abstract

As unmanned aerial vehicles (UAVs) become increasingly integral to sectors such as agriculture, defense, and emergency healthcare, the need for more flexible power sources also increases. Relying solely on one method of propulsion limits the capability of UAVs. A hybrid propulsion system can implement multiple power sources to better address specific mission needs. This thesis details the mission-oriented design and optimization of a hybrid propulsion system combining a Proton Exchange Membrane Fuel Cell (PEMFC) and a lithium-ion battery for a fixed-wing UAV. The research utilizes MATLAB, Simulink, and Simscape platforms to develop a high-fidelity digital representation of the hybrid power system. In addition, the research integrates a detailed PEMFC 400-cell stack with a battery pack circuit. The performance of this hybrid model is evaluated through a parametric study involving three distinct mission profiles: agriculture, package delivery, and surveillance. The results demonstrate that the hybrid configuration leverages the high energy density of the fuel cell for sustained cruise flight while utilizing the battery's superior power density to meet rapid demand spikes during takeoff and climbing. Overall, the hybrid system provides approximately twenty percent higher thermal efficiency and reduced mechanical strain compared to individual power sources. While the current model is best suited for missions lasting between 1 and 1.5 hours, this study provides a framework for future work, emphasizing the potential for energy management systems and more powerful batteries to further extend flight endurance and mission capabilities.