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ISSN: 2772-8307
Copyright © 2026 Shanghai Jiaotong University. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
cited:21
Optimizing coil configurations for AC loss reduction in REBCO HTS fast-ramping magnets at cryogenic temperatures
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Article Number:Article 100024
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Abstract
Corresponding email:Zhenan.Jiang@vuw.ac.nz; Honghai.Song@stonybrook.edu
AC loss is one of the critical issues for designing REBCO fast-ramping magnets operating at cryogenic temperatures. There are many ways to reduce AC loss for coil windings. However, it is not clear which method is the most effective way to minimize AC loss in the coil windings for a given Ampere-turns. In this work, we numerically studied coil configurations of several small superconducting magnets constructed from 12 mm SuperPower REBCO coated conductors, for fast-ramping application with the same Ampere-turns to identify the lowest AC loss among them. The HTS magnets have a total turn number of 50 and inner diameter of 30 cm, carrying AC current operating in the temperature range of 20–40 K at 25 Hz. We incorporated several existing loss reduction strategies including spacing between the turns for single pancake coils, grading Ic values for the solenoid configuration, and applying flux diverters to shape the magnetic field around the coil windings. The simulation was implemented using a homogenized H-formulation. Across all studied loss reduction methods, the use of flux diverters has the largest impact in AC loss reduction. The AC loss values in the solenoid winding comprising a stack of five single pancake coils with 0.1 mm turn-to-turn gap with the flux diverters agree well with those in the single pancake coil for 2 mm turn-to-turn gap with the flux diverters. Solenoid type coil configurations with flux diverters generate much smaller AC loss than the single pancake type with flux diverters when they generate the same center magnetic field.
cited:32
Review on thermal-related measurement methods for superconducting devices and prospect for high-speed maglev transportation application
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Article Number:Article 100020
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Abstract
Corresponding email:jzheng@swjtu.edu.cn
High-temperature superconducting (HTS) bulks can not only be self-stable when levitated above a permanent magnet (PM) but also can be used as quasi PM with higher magnetic energy product due to their magnetic flux pinning characteristics. Therefore, HTS bulks have wide application potentials in maglev trains, maglev bearings, flywheel energy storage, drug delivery, and high field magnets. In the external magnetic field of common application scenarios, HTS bulks have no external input current, so it is difficult to achieve the overall quench. However, local quenching in the bulk is still possible in the harsh fluctuating external field environment. Although it is difficult to reach the total quench, its critical parameters like Jc will inevitably deteriorate, which may collapse the application system. Therefore, in contrast to superconducting wires and tapes that are more concerned with quench detection, HTS bulks with a 3D volume effect are more focused on internal sensitive temperature locations, the impacts of volume and scale, and the coupling influence on application parameters such as magnetism and force. Therefore, for efficient thermal-related measurement of HTS bulk applications, this paper investigates and discusses 12 commonly-used temperature measurement or quench detection methods in all superconducting application fields. These methods primarily refer to the current quench detection technologies used in HTS tapes and wires. From the standpoint of practical temperature measurement requirements of HTS bulks and technological limitations of maglev application scenarios, working characteristics and service conditions of the 12 methods, and 4 temperature detection methods are selected through a comprehensive understanding and comparison of basic principles. They are expected to be used in real-time monitoring and early warning schemes for onboard superconducting levitation devices of HTS maglev transportation or other applications in the future.
cited:60
Review of high temperature superconducting flux pumps
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Article Number:Article 100022
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Corresponding email:weiwangca283@gmail.com
High temperature superconducting (HTS) magnets conduct DC currents ranging from hundreds to tens of thousands of amperes. To achieve such DC output amplitudes, conventional power supplies are unsuitable, owing to their extreme cost, energy consumption, and bulkiness. The indispensable current leads of conventional power supplies carrying large DC current cause an extra heat leakage into the cryogenic system, thus increasing the number of required cryocoolers. A potential solution to tackle this problem, however, is to use HTS flux pumps that inject a large amount of DC current into the HTS magnet in a wireless fashion, thereby eliminating the need for current leads, and allow the magnets to work in the quasi-persistent current mode. Compared with the conventional power supplies, the flux pumps offer the advantages of low cost, low energy consumption, and compact size, etc., which essentially have broad application prospects in nuclear magnetic resonance (NMR/MRI), fusion, particle accelerators, superconducting electric machine, maglev train, etc. Over the last decade, a variety of HTS flux pumps have been invented with improved DC outputs, reaching over kilo-amperes. Moreover, those flux pumps have different working principles, structures and operation strategies. In this paper, we provide an in-depth review on the HTS flux pumps developed in the last decade. In particular, for the HTS travelling wave flux pumps and HTS transformer-rectifier flux pumps, the discussions are focused on their working principles and technical advances. In the end, we discuss the present applications of HTS flux pumps, along with their potential future applications.
cited:35
Performance of highly flexible sub-cable for REBCO Cable-In-Conduit conductor at 5.8 T applied field
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Article Number:Article 100023
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Corresponding email:jinhuan@ipp.ac.cn
Due to the high current capability and excellent flexibility, High Flexible REBCO Cables (HFRC) have emerged as an important candidate for composite high-temperature superconducting conductors. The REBCO six around one Cable-In-Conduit Conductor (CICC) concept has been designed for application in the Central Solenoid (CS) coil of the China Fusion Engineering Test Reactor. In the application of fusion devices, the performance of CICC under electromagnetic (EM) loading and thermal stress is very important for reliable and economic operation. Therefore, a 1.22 m long sub-cable with HFRC design for CICC was manufactured and tested at 4.2 K in a background magnetic field up to 5.8 T. The aim is to investigate the stability of the current-carrying properties of the HFRC cable under electromagnetic and thermal cyclic loading. The test results show that the critical current (Ic) of the HFRC cable reached 17.3 kA in a background magnetic field of 5.8 T at 4.2 K. Furthermore, no performance degradation was observed after 24 cycles of 80 kN/m peak load with a background field of 5.8 T and 8 warm-up-cool-down cycles between 77 K and room temperature. The test results provide a good basis for the development of full-size conductors in future magnet applications.
Review