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 PEM (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. The architectures are an unregulated and a regulated hybrid power source. 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.