Power and energy management system for fuel cell unmanned aerial vehicle

In this article, a hybrid electric propulsion system which consists of a fuel cell (FC) and a battery is proposed for an unmanned aerial vehicle (UAV) propulsion application. Based on the UAV propulsion power requirements during take-off, climb, endurance, and maximum velocity, the hybrid electric power plant specifications are defined to respond to any propulsion power demand. A power and energy management system is introduced to control the hybrid system power flow while optimizing the FC system performances. The power and energy management system consists of three sections called, power management system, power electronic interface, and energy management system. The power management system decides the operating power of the each power source based on the propulsion power demand and the battery state of charge. The power electronic interface is an implementation protocol of the power management decisions through a unidirectional power converter and a bidirectional power converter which are connected to the FC, the battery, and the DC bus. Based on the FC current decided by the power management system, the energy management system controls the air supply system of the FC to maximize the FC system net power output. A referenced model is used to obtain the optimum inlet air pressure of the FC and a neuro-fuzzy-based adaptive control architecture adapts the FC air compressor power to the optimum value. The results show that the optimum compressor power configuration is superior than the constant power configuration.