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Large-scale electric aircraft is a disruptive technology to address the environmental impact of air travel. Fault current limitation is crucial to realise the safety and reliability of the electric aircraft, in particular for large-scale electric aircraft using DC distribution network. This paper investigates the behavior of the resistive SFCL under different cryogenic cooling systems including liquid nitrogen and helium gas circulation cooling systems for the electric aircraft DC distribution network. Electromagnetic and thermoelectric models were used to predict the characteristics of resistive SFCL. The simulation results demonstrate that it is promising to design resistive SFCL using liquid nitrogen cooling as well as helium gas circulation cooling systems, which offer flexibility for SFCL cryogenic cooling system for electric aircraft applications.

Cryogenic operation of power electronics converters plays a key role in the development of the future electric aircraft systems. Characterization of semiconductor switches in the cryogenic environment is pivotal for implementation of the cryogenic power electronics converters. This paper characterizes two groups of Planar and Trench SiC MOSFETs from room temperature to –175°C. The objective is to explore the impact of the cryogenic environment on static and dynamic behavior of the SiC MOSFETs. The dynamic characteristics of these semiconductor switches are investigated by using a double pulse test circuit. The test circuit is placed inside a cryogenic chamber, which is able to accurately adjust the temperature. Important dynamic characteristics such as voltage and current rise and fall times, turn-on, turn-off, and total switching energy losses are investigated. It is shown that the impacts of the cryogenic environment on the two groups of SiC MOSFETs are not identical. Furthermore, the impact of gate driver output voltage on the switching energy losses is discussed. The static characteristics of the SiC MOSFETs are explored by using the same cryogenic chamber and a curve tracer. Breakdown voltage, gate-source threshold voltage, on-state resistance, body diode forward voltage, and average transconductance are the static parameters that are measured.

Cryogenic operation of power electronics is a promising solution for future electric aircraft systems. It offers further advantages to propulsive architectures that exploit high-temperature superconductivity. Investigation of the characteristics of semiconductor devices is a crucial part of the cryogenic power electronics. This paper characterizes a set of GaN E-HEMTs at both cryogenic and room temperatures. The objective is to explore the impact of cryogenic temperature on their static and dynamic characteristics. To investigate the static performance of the GaN E-HEMTs, a curve tracer has been used with devices placed inside a cryogenic chamber. To investigate the dynamic performance of the GaN E-HEMTs at different temperatures, a clamped inductive load circuit is placed inside a cryogenic chamber. The cryogenic chamber changes the temperature from room temperature to $- 175^{\circ}C$.

This paper presents the magnetic core characteristics of three magnetic materials at cryogenic temperature. Amorphous, nanocrystalline, and ferrite ring cores are tested at room temperature as well as 77 K under various operating frequencies. The core characteristics, including saturation flux density, permeability, and power loss are analyzed. The results show the core characteristic differences between the room and cryogenic temperatures as well as the performance differences among different magnetic materials, which will help optimize the high-frequency inductor design for cryogenic applications. Furthermore, the thermal shock test is performed to test the reliability of the cores. One ferrite core inductor and one nanocrystalline core inductor are built and tested in a 9 kW buck converter at cryogenic temperature.

This paper presents in details a study, in order to detect an electrical serial arc, on a DC network, by using an electric antenna. An electric signature, linked to the arc phenomenon and independent of the circuit impedance, is identified as a good marker for the detection. An electric antenna is proposed, in order to detect this signature: the detection principle is explained and studied by both experiments and simulation, and an optimized design is proposed. The chosen antenna is tested by creating a serial arc on an airborne terminal block. At last, perspectives are given in order to assess the detection performances and robustness.