A Preliminary Study on the Experimental Characterization and Modelling of a 20kW Fuel Cell System for Ultralight Aviation

This research is conducted as part of the SERENA project, which aims to develop an electric and modular hydrogen-based powertrain for general aviation. The modular design allows for adaptable power output levels, catering to diverse operational requirements and future scalability. In earlier work, the main powertrain components — the PEM fuel cell, the battery, and the compressed hydrogen cylinder — were dimensioned using a method that prioritizes minimizing both mass and volume. This article details the experimental evaluation of a 20 kW fuel cell module, with particular emphasis on the cathode circuit. It includes a two-stage dynamic compressor, a humidifier, the fuel cell stack, and a backpressure control valve. The testing setup comprises a bi-directional programmable load and a data acquisition system that monitors pressure and temperature throughout the cathode pathway and the compressor’s duty cycle. Data collected at sea level were used to calibrate a numerical model that predicts fuel cell performance across flight conditions. As altitude increases, the compressor’s parasitic power demand rises, necessitating a corresponding increase in stack current to maintain the target power output. Preliminary findings indicate that raising the flight altitude from sea level up to 2000 meters can cause the compressor’s parasitic power to increase by as much as 150% under low-load conditions.