Simultaneous Combined Optimal Design and Control Formulation for Aircraft Hybrid-Electric Propulsion Systems

Abstract

A key challenge in the design of hybrid-electric propulsion systems (HEPSs) for aircraft is the complexity involved in handling efficient sizing of the components as well as control synergy between multiple power sources. To handle this challenge effectively, combined optimal design and control (codesign) methods that enable the integration of energy management optimization along with vehicle sizing are required. Even though some studies have explored such methods, they have done so in a computationally intensive nested formulation with limited depth on the design and control modeling aspect. This paper addresses these issues by posing the system codesign problem using a simultaneous formulation of multidisciplinary dynamic system design optimization (MDSDO). The simultaneous formulation generally facilitates superior computational performance while the MDSDO method solves codesign problems from a more balanced perspective between design- and control-related variables. This method is applied in this paper to aircraft HEPS design with an objective of determining the optimal propulsion component designs and supervisory control strategy that minimizes total energy consumption. The hybrid configuration is compared with its conventional counterpart on the basis of system efficiency. In addition to that, a parametric study on the battery energy density is presented to explore the near-term viability of HEPS for aircraft.