Energy management strategy for parallel hybrid electric aircraft considering SOC sustainment

The parallel hybrid electric propulsion system for aviation is constrained by limited battery capacity and stringent safety requirements. This paper proposes an adaptive k-value system instantaneous efficiency maximization strategy (AK-SEMS) to overcome the limitations of adaptive equivalent consumption minimization strategy (A-ECMS). The method explicitly incorporates secondary electric energy conversion losses into the equivalent fuel consumption framework, proposing a non-predictive, forward-aware strategy that enables real-time efficiency optimization while accounting for future energy demands. A convex optimization correction mechanism is derived to ensure stable SOC regulation, while a fuzzy adaptive mechanism based on state-of-charge (SOC) dynamically balances efficiency and SOC sustainability. Validation against A-ECMS and dynamic programming demonstrates that AK-SEMS enhances performance across reconnaissance cruise missions. On average, it achieves a fuel-saving coefficient of 0.60, together with a 5.52 % reduction in direct fuel consumption, a 12.20 % improvement in system efficiency, a 21.43 % reduction in battery degradation, and reliable SOC sustainment compared with A-ECMS. Furthermore, hardware-in-the-loop simulations demonstrate its capability to achieve real-time response, highlighting its practical feasibility for aviation applications.