Optimal Arrangement of Electric Motors for Distributed Electric Propulsion Aircraft: Using NMPC and Generalized Benders Decomposition

Distributed electric propulsion (DEP) aircraft have the potential for high propulsive efficiency and wake-filling benefits. However, the effective operation of DEP aircraft depends upon the proper arrangement of electric propulsion motors. To address this issue, this paper presents an optimal arrangement method, which is intended to be used for the preliminary determination of the number and size of electric propulsion motors in DEP aircraft. The salient feature of the proposed method is that, by incorporating the DEP control strategy into the arrangement process, it yields the optimal number and size of electric propulsion motors in a dynamic context. Specifically, we formulate the arrangement problem as a linear programming problem, aiming to minimize the total weight of motors. In the meantime, the DEP controller is developed for climb control and energy saving using nonlinear model predictive control (NMPC). Afterwards, we embed the NMPC problem into the arrangement problem, hence obtaining an integrated optimization problem, which interconnects the arrangement domain with control domain. Utilizing the generalized Benders decomposition, we can efficiently solve this integrated problem. The effectiveness of the proposed method is demonstrated in the simulations.