Ground simulation of fuel cell/battery hybrid propulsion system for small unmanned air vehicles

Purpose The endurance of small unmanned air vehicles (UAVs) is directly associated with the energy density of the propulsion system used. As the batteries commonly used in small UAVs have a relatively low energy density, they are not sufficient for long-term endurance tasks. The purpose of this paper is to offer a solution to increase the endurance of a concept small UAV with combination of different power sources. The design, construction and ground tests of fuel cell-powered hybrid propulsion systems are presented in this paper. Design/methodology/approach The power requirements of a concept UAV were calculated according to aerodynamic calculations and then, hybrid propulsion system sources are determined. The hybrid system consists of a 100 W scale proton-exchange membrane (PEM) type fuel cell stack, lithium-polymer battery, solar cells and power management system (PMS). Subsequently, this hybrid power system was integrated with the new design of PMS and then series of ground tests were carried out. Findings This experimental study proved that it is theoretically possible to obtain an endurance of around 3 h for concept UAV with the proposed hybrid system. Practical implications The research study shows that fuel cell-based hybrid propulsion system with the proposed PMS can be widely used to obtain extended endurance in small UAVs. Originality/value A hybrid propulsion system with a novel PMS unit is proposed for small UAVs and the ground tests were implemented.