A Method for Simultaneous Optimization of Power Management Schedule and Flight Trajectory for Hybrid Electric Aircrafts

The aviation industry relies on a diverse set of objectives to operate at optimal efficiency and profitability. Two of these objectives include reducing emissions and generating optimal flight trajectories. There is increasing interest in aircraft hybridization to address emissions due to its potential to meet future environmental goals. The primary challenge of creating a hybrid aircraft is to generate required thrust while finding the optimal power split between two energy sources, electric and gas turbine power. This challenge exists because although electric power has a lower life cycle emission than gas turbine, the increasing weight from the electric components results in higher fuel consumption. The optimal power split trajectory and the optimal flight path trajectory both have the potential of reducing fuel burn and emission. In fact, the expected reduction is the greatest when you simultaneously optimize the mission trajectory and the power split trajectory. This paper proposes a single approach that attempts to fulfill the two aforementioned objectives. Differential dynamic programming (DDP) is proposed to generate a flight trajectory while considering the optimal power split to minimize fuel burn. A notable strength of the DDP lies in its computational speed. Hence, it could assist pilots during flight with online trajectory creation. DDP is applied to a 9 passenger jet aircraft airframe with a series hybrid architecture turboprop engine. The series hybrid architecture is chosen based on its potential for emission reduction observed in the automobile industry. The performance of the optimized hybrid aircraft is compared to the performance of the traditional aircraft for a nominal aircraft mission. Trade study is performed on the algorithm’s hyperparameter setup to compare the aircraft performance for various settings