Defining Control Loops for a Fuel Cell Powered Aeronautic Propulsion System

Abstract

he main function of the Full-Authority Digital Engine Controller in turbofan engines is to ensure that the thrust required by the aircraft is provided while avoiding exceedances on engine parameters. Limits on maximum and minimum values of shaft speeds, temperatures, and pressures are defined to protect the engine from damage and to ensure its correct operation. The maximum available thrust becomes a function of environmental variables like altitude, ambient pressure and temperature, and of some operational parameters such as airspeed and auxiliary power demands (air conditioning, anti-ice, etc). This work explores the definition of similar control loops for an electric power train. It is assumed that the main source of energy is a hydrogen fuel cell and that it is supported by a battery to shave power demand peaks at certain phases of flight. A top-down methodology is used, in which the different operational scenarios (both steady-state and transient) are considered and the management problem for each one is discussed.