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With significant interest in the use of high-temperature superconducting (HTS) components in electric aircraft, there is a need for novel modelling techniques that allow architecture-level studies of the electrical systems including HTS components. In this study, a simple electric network architecture, as proposed in the literature has been considered, which includes generators, dynamic propulsion load and cables. This electric network has been modelled considering conventional technology and using HTS cables by replacing the conventional copper cables, to evaluate the variations in the network performance. The network performance has been studied for the dynamically varying propulsion load, which is nearly equivalent to the aircraft load over the entire flight duration. Following this, electric faults have been applied at various locations, and the impact of HTS cables on the network fault levels has been evaluated. The fault current levels are compared using both conventional and HTS cables, due to the fault current limiting properties of the HTS cables, they are observed to offer lowered fault current values.

Distributed propulsion for aircraft is a radical concept in which the generation of thrust is decentralized from the main power sources. Various implementations of this concept are being considered as ways of reducing aircraft fuel burn and noise impact in the future, many relying on electrical transmission. However, the power required for aircraft propulsion is orders greater than the present electrical systems on aircraft. Efficiency and weight of the electrical components will be crucial for the feasibility of an aircraft with distributed propulsion and thus, HTS technology is of strong interest. This paper explains the interest in the technology and possible means of implementation in an aircraft, including considerations of the means of cryogenic cooling. Technology targets are presented on the basis of an aircraft that uses distributed propulsion to enable boundary layer ingestion and produces 50% of its thrust electrically.

Electric aircraft has already become a reality, with demonstration flights at power ratings of less than 1 MVA. Conventional machines and distribution technologies suffer from poor power densities when scaling to large power demands, leading to significant challenges in applying this technology from small (100-seater) planes. Superconducting devices could be an enabler for electric aviation due to their great potential for high efficiency and low weight. However, while the development of the superconducting components presents a significant challenge, the safe and effective combination of such components into a propulsion system also requires a significant area of research. For this purpose, a signal-based MATLAB-Simscape model for a dc network architecture in a turbo-electric aircraft has been established and the highly nonlinear models for the superconducting devices have been developed and integrated. This network model has been used to understand the fault current magnitude and rise time, as well as the stability behavior of the system utilizing the realistic electro-thermal models of superconducting devices in it. The derived network was investigated for a bus bar short circuit fault using both superconducting fault current limiter and fault current limiting high temperature superconducting (FCL HTS) cable. Based on the network characteristics, a fault tolerant dc network design was achieved by utilizing the FCL HTS cables. Similarly, the operation limits of the protection devices have been reduced greatly using superconducting components.

As fuel efficiency becomes a greater concern in commercial aircraft design and operation it is important to gain a deeper understanding of energy use throughout an aircraft’s systems. To meet this need, a new methodology is being developed that proposes the use of exergy as a metric for mapping the energy flows throughout an aircraft at any required level of detail over a given flight. Exergy allows direct comparison of differing energy types and clearer interpretation of losses and availability. Time-variant application of exergy to vehicles, however, presents complexities, such as large data volumes, temporary exergy storage, exergy exchange between system and mass, and an inconsistent reference state. A software tool prototype is introduced to allow the management of an aircraft exergy map. To describe its use an unmanned aerial vehicle is evaluated. A turbojet study isolates the reference state problem and illustrates the need to use a moving, aircraft-fixed reference state. However, it is shown that ...

A coaxial cable made out of helically wound 2G HTS tapes is being widely implemented based on its low critical bending radius, ease of manufacturing and installation. Though the design technique is mature, the cable still lacks standard Ic definition. With increased usage of such cables, robustness in its operation is expected. HTS tapes are highly sensitive to externally applied mechanical stress and strain values. These limitations force the coaxial cables to be operated at 50-75% of its rated capacity. One of the major problems in coaxial cable design is the contact resistance of the tapes with the terminal, which affects the current distribution among different tapes in the same layer. Further current redistribution at constant intervals helps the applied current in bypassing the localized faults in the individual HTS tapes, thus making efficient use of the major length of the tape. This paper proposes the use of voltage shunts between HTS layers at constant intervals for regular current redistributions along the length of the cable. This method significantly helps to sustain the Ic value of the cable, even if it has got several minor defects in the tapes.

There is a perceived need in the future for a move away from traditional aircraft designs in order to meet ambitious emissions and fuel burn targets. High temperature superconducting distributed propulsion may be an enabler for aircraft designs that have better propulsive efficiency and lower drag. There has been significant work considering the electrical systems required, but less on the cryogenics to enable it. This paper discusses some of the major choices to be faced in cryocooling for aircraft. The likely need for a disposable cryogen to reduce power demand is explained. A set of cryocooling methods are considered in a sensitivity study, which shows that the feasibility of the cryogenic system will depend strongly on the superconducting technology and the aircraft platform. It is argued that all three aspects must be researched and designed in close collaboration to reach a viable solution.

Increases in fuel costs and environmental concerns have in recent years heightened the importance of fuel efficiency as a design consideration in vehicles, especially aircraft. For this reason, a greater understanding of the energy consumption of vehicles is needed, both for design and operational decisions. Exergy, a measure of available work in an imbalance of state, allows systems to be compared on an equal basis with losses and waste being equated to fuel costs. Vehicles and especially aircraft do not operate in steady state as do industrial plants, the traditional subject of exergy analysis. While some analysis of aircraft has been performed in the literature, time-variance has not been addressed, leading to a lack of detail and only very broad conclusions. It is proposed that in order to fully understand aircraft energy use, a fully time-variant analysis must be performed. It is the aim of this paper to discuss the first challenges encountered in designing a methodology to permit this and to describe the methods used to address these issues.