Development and evaluation of a proton exchange membrane fuel cell system for unmanned aerial vehicles applications

This study presents the in-house development and characterization of a proton exchange membrane fuel cell (PEMFC) energy supply system for unmanned aerial vehicles. The system performance, including the 30-cell PEMFC stack stability and efficiency, is evaluated. Stable operation was achieved up to 16 V (about 160 W), while lower voltages led to a gradual performance degradation due to excess heating. A maximum efficiency of 39 % was achieved, with the reaction heat being the main energy loss, accounting for 47 % of the total energy input. An auxiliary battery is successfully integrated to provide additional power and compensate for the slower response of the PEMFC to dynamic load changes. When increasing the system current from 0 to 15 A, the PEMFC initially supplies around 55 % of the system current. After 1 min, this value increases to 70 %. A circuit for automatically charging the battery using the PEMFC power is implemented and evaluated. When the battery voltage is low and the system has extra power, the battery is charged with a 2 A current that decreases as the voltage increases. A flight simulation based on real flight data is performed, and the system meets all power demands. The PEMFC reached higher levels of performance during this test compared to the static tests, likely due to differences in temperature and humidity. The study also discusses system limitations and suggests potential improvements.