This paper proposes new analytical expressions of indicators for inter-turn and phase-to-phase short-circuit fault diagnosis in permanent-magnet synchronous machines. The proposed indicators are deduced from symmetrical components of phase currents in the αβ reference frame. They are able to reflect the fault severity and location, are independent from the electrical pulsation and the rotor initial angle, and are robust regarding the loss of some measurements. Hence, they can be used for fault isolation and identification. Experimental tests have been carried out and show promising results. Furthermore, the presented algorithm does not use fast Fourier transforms and, therefore, avoids delays in fault isolation inherent to this technique.

With the increasing number of electrical loads, load management of the more electric aircraft becomes crucial for reliability and efficiency. One of the major challenge is to develop an optimal and reliable adaptive power control. This paper presents a three-level load management method with dedicated time steps for fault tolerance and increasing calculation efficiency. Both the operative mode and the health level of the loads are taken into account in the control using fuzzy logic. The electrical system of a V-tail more electric aircraft that consists of a generator, an auxiliary power unit, and several AC/DC buses and loads is examined by the proposed method in normal and faulty cases. Compared with some conventional methods, the proposed load management method has the advantage of efficiently shedding loads according to the power imbalance and the fault situation.

The exhaust of turboshaft engines contains a big amount of waste heat but does not provide propulsion power to the helicopter. Reusing the heat can increase fuel efficiency and reduce carbon emissions of the engine. This paper implements energy analyses and weight penalty estimations to a waste heat recovery module of the turboshaft engine. The components are a fuel preheating process and a power generation unit based on the organic Rankine cycle. The fuel penalty of the module consists of the fuel consumption of the following: carrying the instruments, overcoming the additional drag, and powering from the engine. Considering the high-temperature situation, working fluid of the module is chosen from benzene, R365mfc, and R245fa. Simulation based on T700 turboshaft engine and a complete flight mission validate the energy efficiency improvement produced by the module. Results show that the module having existing technologies of the expander always cost additional fuel while increasing energy efficiency for the helicopter, but negative fuel penalties can be achieved by increasing the power-to-weight ratio of the module.

In this study, a design scheme for a high-aspect-ratio bionic multi-section variable-sweep wing unmanned aerial vehicle (UAV) that utilizes the reverse coordinated change in the sweep angle of the inner and outer wing sections is proposed, which improves the aerodynamic performance and realizes the self-trim compensation of the wing’s centroid. According to the layout characteristics of this type of UAV, a reasonable distribution design of the wingspan ratio of the inner and outer sections is explored, to reduce the impact of aerodynamic center movement and moment of inertia change. The calculation and analysis results show that the coordinated variable-sweep scheme can significantly improve the influence of sweep angle change on the longitudinal static stability margin of UAVs with a high aspect ratio. The coordinated sweep angle change in the inner and outer wing sections can not only reduce the drag during high-speed flight, but also play a significant role in improving the performance of the aircraft at different stages in the mission profile. Appropriately increasing the wingspan proportion of the inner section can reduce the trim resistance of the V-tail, reduce the thrust of the engine, and increase the range and duration of the UAV. From the perspective of stability change, the multi-section variable-sweep wing UAV with a wingspan ratio of the inner and outer sections that is between 1.41 and 1.78 has better dynamic stability performance. Among them, the UAV with a wingspan ratio of the inner and outer sections that is equal to 1.41 has better longitudinal stability performance, while the UAV with a wingspan ratio of the inner and outer sections that is equal to 1.78 has better lateral/directional stability performance.