Power Balance of a Hybrid Power Source in a Power Plant for a Small Propulsion Aircraft

This paper analyzes two different architectures for a hybrid power source comprising a polymer electrolyte membrane fuel cell and a Li ion battery. The hybrid power source feeds the propulsion motor of an all-electrical aircraft, the Boeing Fuel Cell Demonstrator. Unregulated and regulated hybrid power architectures are examined. The regulation is achieved by means of a controllable series boost converter (SBC) connected in series with the fuel cell. Both architectures have been simulated, implemented, and tested in the Boeing Fuel Cell Demonstrator airplane.