Quantitative analysis of AC losses in HTS coils below 40K for advanced electric aircraft propulsion systems

Electric or hybrid aviation technologies are increasingly recognized as pivotal for achieving net-zero emissions in the aerospace sector. Superconducting machines, characterized by their high power-to-weight ratio, are poised to fulfill the advancing propulsion requirements of this domain. The design of future cryogenic systems and the attenuation of alternating current (AC) losses in high-temperature superconducting (HTS) machines necessitate experimental data on AC losses across a spectrum of operational temperatures. Consequently, gaseous helium’s employment as a cryogen emerges as a versatile solution, catering to the operational demands of HTS power applications.
Building upon our antecedent research, which delineated the fabrication of multi-filamentary HTS coils and corroborated a significant diminution in AC losses, the present study endeavors to quantify additional AC loss reductions across diverse HTS windings within a rotational machine environment, specifically under the cryogenic threshold of 40K. This investigation introduces a novel fully HTS machine, integrated with a cryogenic helium circulation system for cooling, designed to facilitate an environment conducive to measuring the AC losses in HTS stator windings at sub-40K temperatures. Subsequent to the experimental phase, Finite Element Modelling (FEM) will be employed to corroborate the findings, thereby providing a computational framework to augment future system designs. It is anticipated that the cooling strategy, leveraging a cryogenic gas circulation system, will enhance the performance and power density of fully HTS machines, culminating in an optimized machine efficiency.






References
1. T. Lan et al., "Multifilament HTS Cables to Reduce AC Loss: Proof-of-Concept Experiments and Simulation," in IEEE Transactions on Applied Superconductivity, vol. 33, no. 6, pp. 1-12, Sept. 2023, Art no. 5901512