The flight verification of an integrated propulsion system powered by PEMFCs with direct airflow intake design

The propulsion and power systems are critical to the performance of unmanned aerial vehicles (UAVs). The rapid development of electrified propulsion systems powered by proton exchange membrane fuel cells (PEMFCs) has driven technological innovation of propulsion and power systems for UAVs. In this work, a 1.5 kW PEMFC integrated propulsion system with direct airflow intake design (Beihang Hydrogen-1) is developed and verified by flight test on a UAV with a wingspan of 3.6 m. The propulsion system can directly use the airflow behind the propeller to feed the PEMFC cathode for cooling and reaction and the power generated by the PEMFC is used to drive the propeller. A DC-DC module and a lithium battery pack are also added to the propulsion system to stabilize the output voltage and increase the instantaneous power for takeoff, transition, and landing stages. The “dynamic distribution” energy management strategy for the propulsion system is proposed to increase the system dynamic response ability. The detailed data of the PEMFC integrated propulsion system during the flight are measured and analyzed. The flight test continued for 18 min, with an average cruising altitude and an average cruising speed of 101 m above sea level and 23 m/s, respectively. During the cruise stage, the average PEMFC power is 1688 W, with an average single-cell voltage of 0.65 V. The average charging power of PEMFC for the lithium battery is 41 W. The successful flight test verifies the feasibility of the design of the PEMFC integrated propulsion system, provides valuable data for the following optimal design and flight test of the PEMFC integrated propulsion systems, and opens up a new direction for the development and application of PEMFC-powered electrified propulsion systems.