The rapid development of industry results in large energy consumption and a negative impact on the environment. Pollution of the environment caused by conventional energy sources such as petrol leads to increased demand for propulsion systems with higher efficiency and capable of energy-saving and emission reduction. The usage of hybrid technology is expected to improve energy conversion efficiency, reduce energy consumption and environmental pollution. In this paper, the simulation platform for the hybrid unmanned aerial vehicle (UAV) has been built by establishing the subsystem models of the UAV power system. Under the two chosen working conditions, the conventional cruise flight mission and the terrain tracking mission, the power tracking control and Q-Learning method have been used to design the energy management controller for the hybrid UAV. The fuel consumption and pollutant emissions under each working condition were calculated. The results show that the hybrid system can improve the efficiency of the UAV system, reduce the fuel consumption of the UAV, and so reduce the emissions of CO2, NOx, and other pollutants. This contributes to improving of environmental quality, energy-saving, and emission reduction, thereby contributing to the sustainable development of aviation.

This paper proposes a distributed turbo-electric hybrid propulsion system (TEHPS) architecture for high-power and large-load air–ground aircraft (AGA). The composition of the turboshaft engine, hybrid energy storage system (HESS) as the power unit, distributed electric drive ducted fans, and wheels as the propulsion unit is determined. Firstly, the modeling of each component in the TEHPS is carried out, and system power, energy, and weight analysis are conducted under the different operating modes. Sizing parameters of main components are selected based on a genetic algorithm to obtain the optimal total weight and propulsion efficiency, and the energy management framework from the upper level to the lower level is completed by adopting an equivalent consumption minimum strategy and fuzzy logic control. Under the air–ground amphibious mission profile, the simulation results indicate that the TEHPS can achieve a 21.80% fuel consumption and ${\mathrm{CO}}_2$ emission optimization rate at the cost of 10.53% increase in the whole aircraft mass compared to the oil-only powertrain. The HESS can account for up to 29% and 33.56% of the energy and power ratios in the TEHPS, and reduce mass by 8.1% and volume by 3.77% compared to the single energy storage, which may provide theoretical insights for the powertrain composition form, sizing, and energy management of future hybrid air–ground aircraft.

In the application of the superconducting ac homopolar machines (SAHMs), high temperature superconductor (HTS) exciting windings carry dc currents under external ac magnetic fields and generally cause dynamic loss and magnetization loss, which will deteriorate the stable operation of SAHM. The conductor on round core (CORC) cables is a promising choice for HTS exciting windings because of its high current-carrying capacity with low ac losses and excellent mechanical stability. In this study, the dynamic resistance and magnetization losses of CORC cables carrying a dc current under an ac magnetic field were studied using numerical and experimental methods at 77 K. The numerical methods [three-dimensional (3-D) H homogenization model, 3-D T-A full model, 3-D T-A homogenization model] were compared with experimental data to validate them. Subsequently, the current distribution of CORC cables was studied under different working conditions. The effect of weak anisotropy and the shielding effect of CORC cables on dynamic resistance was researched. In addition, the dependence of CORC structure parameters on dynamic resistance and magnetization losses was analyzed, which is very helpful for the engineering applications of CORC cables as the exciting windings in homopolar machines. Besides, the results provide a reference for dynamic loss behaviors in CORC superconductor.

This paper presents a distributed hybrid electric propulsion system (DHEPS) retrofitted for a general aviation aircraft, incorporating additional distributed propulsion units to enhance overall performance. Subsystem modeling and component parameter selection are conducted for a hybrid electric ground testbed. A hierarchical control framework is proposed, featuring a top-level supervisory controller based on state machine energy management strategy (SM-EMS). At the bottom level, control strategies for electro-mechanical coupling across multiple time scales are developed, integrating reinforcement learning-based field-oriented control (RL-FOC) and extended Kalman filter (EKF) methods for distributed motors, as well as adaptive PI control for regulating the engine-generator shaft speed. Simulation results for a cruise flight profile demonstrate that the DHEPS achieves a 7.4% reduction in fuel consumption and a 2.1% improvement in energy-specific air range compared to the baseline aircraft. The RL-FOC and EKF-based methods for distributed motors significantly improves response time and steady-state accuracy over conventional PI control, while the adaptive PI control minimizes overshoot and shortens settling time. Dynamic ground testing further validates effective power matching, voltage-current balance, confirming the robustness of the hierarchical control framework and the successful implementation of the DHEPS configuration and the SM-EMS.