Novel custom-made design and analysis of hydrogen PEM fuel cell for high endurance small UAV applications.

The purpose of this paper is to propose a new methodology to devise a custom-made hydrogen-based proton-exchange membrane fuel cell (PEMFC) system for a class of experimental fixed-wing small unmanned aerial vehicles (SUAVs). The proposed fuel cell provides three times higher flight endurance than the conventional battery-based powertrain. The chosen SUAV represents a class of high-altitude UAVs, having an operational altitude of 4500 m (14,760ft), cruising speed of 12-20 m/s (39.4-65.6 ft/s), take-off weight of 4 kg, wing-span of 1.61 m (5.28 ft) and battery-powered flight endurance of 1 h. The characteristic parameters and design configurations of the fuel cell are determined by employing the first principles of electrochemistry and thermodynamics. Corresponding simulations are performed using popular development tools like MATLAB/Simulink. The vital results in the form of - polarization and power curves for fuel cells, against the current density are obtained, which are further narrowed down to meet the target power requirements for determining the size of the hydrogen storage tank. The paper also comments on the auxiliary systems and fuel cell powertrain for SUAVs. Finally, the design efficiency of 54% for the fuel cell is achieved with respect to equivalent voltage for heating value with the calculated hydrogen storage tank size of 5.688 ls. This yields three times higher flight endurance as compared to the flight time found in literature for the same class of SUAVs.