Pub Date : 2025-02-07DOI: 10.1109/TASC.2025.3539601
M. Wozniak;A. Devred;R. Ferriere;C. Geuzaine;A. Haziot;G. Kirby;E. Ravaioli;A. Verweij
A quench protection study was performed on the Fusillo Demonstrator Curved Canted Cosine Theta (CCCT) dipole magnet developed at CERN. This magnet features an aperture of 236 mm and a bending radius and angle of 1 m and 90 degrees, respectively. It has an inductance of 9.14 H, a peak winding field of 3.6 T and multi-harmonic aperture field correction. Ten turns of a rope cable made of Nb-Ti strands are placed in each channel of aluminium formers, which are surrounded by an aluminium shell. The aluminium structures not only support mechanical forces but also affect the quench behavior of the magnet. A discharge of the stored energy over an external resistor results in significant eddy current heating of the aluminium structures, which quickly brings a large part of the superconducting winding to the resistive state. A three-dimensional (3D) simulation of the eddy currents and heat propagation in the formers with heat propagation in the magnet windings was performed. It uses a cooperative simulation approach involving two software tools developed at CERN as part of the STEAM framework: a finite-element-based tool called FiQuS and a finite-difference-based tool called LEDET. FiQuS calculates the eddy currents and the temperature distribution of the formers, whereas LEDET calculates the current, voltage, and temperature of the windings. This approach enables a 3D quench simulation with great geometrical detail while maintaining reasonable computational cost. Energy extraction with a fixed resistor is studied, and key parameters of the discharge are calculated. The voltage of the magnet remains below the target specification of 1.5 kV, and the adiabatic hot spot temperature of the windings reaches 185 K. It is shown that the magnet differential inductance and winding resistance dominate the protection transient. The simulations provide great insights into the transient behaviour of the magnet, including the metal structures' temperature and the eddy currents' temporal and spatial distribution.
{"title":"Quench Protection of the Fusillo Demonstrator Curved CCT Magnet","authors":"M. Wozniak;A. Devred;R. Ferriere;C. Geuzaine;A. Haziot;G. Kirby;E. Ravaioli;A. Verweij","doi":"10.1109/TASC.2025.3539601","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539601","url":null,"abstract":"A quench protection study was performed on the Fusillo Demonstrator Curved Canted Cosine Theta (CCCT) dipole magnet developed at CERN. This magnet features an aperture of 236 mm and a bending radius and angle of 1 m and 90 degrees, respectively. It has an inductance of 9.14 H, a peak winding field of 3.6 T and multi-harmonic aperture field correction. Ten turns of a rope cable made of Nb-Ti strands are placed in each channel of aluminium formers, which are surrounded by an aluminium shell. The aluminium structures not only support mechanical forces but also affect the quench behavior of the magnet. A discharge of the stored energy over an external resistor results in significant eddy current heating of the aluminium structures, which quickly brings a large part of the superconducting winding to the resistive state. A three-dimensional (3D) simulation of the eddy currents and heat propagation in the formers with heat propagation in the magnet windings was performed. It uses a cooperative simulation approach involving two software tools developed at CERN as part of the STEAM framework: a finite-element-based tool called FiQuS and a finite-difference-based tool called LEDET. FiQuS calculates the eddy currents and the temperature distribution of the formers, whereas LEDET calculates the current, voltage, and temperature of the windings. This approach enables a 3D quench simulation with great geometrical detail while maintaining reasonable computational cost. Energy extraction with a fixed resistor is studied, and key parameters of the discharge are calculated. The voltage of the magnet remains below the target specification of 1.5 kV, and the adiabatic hot spot temperature of the windings reaches 185 K. It is shown that the magnet differential inductance and winding resistance dominate the protection transient. The simulations provide great insights into the transient behaviour of the magnet, including the metal structures' temperature and the eddy currents' temporal and spatial distribution.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10878112","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1109/TASC.2025.3539602
S. Je;I. Shin;H. Kim;Y. Kim;Y. Jung;S. Na;S. C. Hopkins;A. Devred;T. Boutboul;S. Park;H. Lee;H. Kim
The DT design provides high Jc through uniform tin distribution, while the DB design enhances mechanical strength and thermal stability. The hybrid design, known as the Distributed Barrier Strand (DBS), balances these properties, significantly improving thermo-magnetic stability while maintaining high Jc. The wires were fabricated using the internal tin process and underwent a multi-stage heat treatment to form the Nb3Sn phase. Evaluations of various designs in terms of critical current density (Jc), thermo-magnetic stability, strain tolerance, and mechanical properties revealed that the DBS hybrid design exhibited higher stability and performance compared to the individual DT and DB designs. This research offers key insights into the design and fabrication of Nb3Sn superconducting wires and has important implications for high-performance applications.
{"title":"Advanced Designs for Enhanced Thermo-Magnetic Stability in High Jc Nb3Sn Wires","authors":"S. Je;I. Shin;H. Kim;Y. Kim;Y. Jung;S. Na;S. C. Hopkins;A. Devred;T. Boutboul;S. Park;H. Lee;H. Kim","doi":"10.1109/TASC.2025.3539602","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539602","url":null,"abstract":"The DT design provides high <italic>J<sub>c</sub></i> through uniform tin distribution, while the DB design enhances mechanical strength and thermal stability. The hybrid design, known as the Distributed Barrier Strand (DBS), balances these properties, significantly improving thermo-magnetic stability while maintaining high <italic>J<sub>c</sub></i>. The wires were fabricated using the internal tin process and underwent a multi-stage heat treatment to form the Nb<sub>3</sub>Sn phase. Evaluations of various designs in terms of critical current density (<italic>J<sub>c</sub></i>), thermo-magnetic stability, strain tolerance, and mechanical properties revealed that the DBS hybrid design exhibited higher stability and performance compared to the individual DT and DB designs. This research offers key insights into the design and fabrication of Nb<sub>3</sub>Sn superconducting wires and has important implications for high-performance applications.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-4"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The integration of high-temperature superconducting (HTS) technology into fusion magnets necessitates advanced cabling solutions. This study presents the design and fabrication of a prototype Stacks-in-Conduit-Conductor (SICC) cable for a current lead. The current lead comprises a 2 × 2 parallel REBCO stacks, each consisting of 30 layered REBCO tapes. Three repeated experiments were conducted in a liquid nitrogen environment, applying a current of 8 kA. Voltage measurements revealed a negative voltage profile in the inter-stack voltages indicating effective current sharing among the REBCO stacks. Similar inter-stack voltage profiles were confirmed through simple circuit analysis. The loss across the REBCO stacks, including contact resistance, was measured to be less than 1 W. However, when a copper block was incorporated, the total loss of the current lead increased to approximately 5.6 W. Further improvements can be achieved by optimizing low-resistance termination joints and the volume of the copper block.
{"title":"Preliminary Study on 2 × 2 Parallel REBCO Stacks for 8 kA Current Leads","authors":"Bonghyun Cho;Sangjun Oh;Heekyung Choi;Won Woo Park;Seokho Nam;Dohyun Baek;Ye Lim Lee;Jung Tae Lee;Seungyong Hahn;Jiho Lee","doi":"10.1109/TASC.2025.3539610","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539610","url":null,"abstract":"The integration of high-temperature superconducting (HTS) technology into fusion magnets necessitates advanced cabling solutions. This study presents the design and fabrication of a prototype Stacks-in-Conduit-Conductor (SICC) cable for a current lead. The current lead comprises a 2 × 2 parallel REBCO stacks, each consisting of 30 layered REBCO tapes. Three repeated experiments were conducted in a liquid nitrogen environment, applying a current of 8 kA. Voltage measurements revealed a negative voltage profile in the inter-stack voltages indicating effective current sharing among the REBCO stacks. Similar inter-stack voltage profiles were confirmed through simple circuit analysis. The loss across the REBCO stacks, including contact resistance, was measured to be less than 1 W. However, when a copper block was incorporated, the total loss of the current lead increased to approximately 5.6 W. Further improvements can be achieved by optimizing low-resistance termination joints and the volume of the copper block.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1109/TASC.2025.3539269
Tianyong Gong;Loïc Quéval
The behavior of a field-controlled high-temperature superconducting (HTS) switch is investigated by experiment and simulation. The HTS switch consists of a YBCO tape placed in the air-gap of an iron-core copper-wound electromagnet. We measured the resistance of the switch for different amplitudes and frequencies of the electromagnet current, and for different HTS tape direct current transport currents. A two-dimensional electromagnetic-thermal finite element model with unidirectional coupling was developed to accurately and efficiently simulate the switch. The fabricated switch can generate an off-state resistance of 93 µΩ, meeting the requirements for certain applications, such as transformer-rectifier HTS flux pumps. The unidirectional electromagneticthermal coupling model reduces computational time by 96% compared to the bidirectional counterpart, without compromising accuracy.
{"title":"A Field-Controlled High-Temperature Superconducting Switch: Experiment and Simulation","authors":"Tianyong Gong;Loïc Quéval","doi":"10.1109/TASC.2025.3539269","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539269","url":null,"abstract":"The behavior of a field-controlled high-temperature superconducting (HTS) switch is investigated by experiment and simulation. The HTS switch consists of a YBCO tape placed in the air-gap of an iron-core copper-wound electromagnet. We measured the resistance of the switch for different amplitudes and frequencies of the electromagnet current, and for different HTS tape direct current transport currents. A two-dimensional electromagnetic-thermal finite element model with unidirectional coupling was developed to accurately and efficiently simulate the switch. The fabricated switch can generate an off-state resistance of 93 µΩ, meeting the requirements for certain applications, such as transformer-rectifier HTS flux pumps. The unidirectional electromagneticthermal coupling model reduces computational time by 96% compared to the bidirectional counterpart, without compromising accuracy.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1109/TASC.2025.3539271
Koki Asai;Tsuyoshi Yagai;Taku Moronaga;Nobuya Banno
Enhancing the characteristics of Nb3Sn superconducting wire is essential for the development of magnets for fusion reactors like ITER and DEMO. It has been established that Ti-doping has a significant effect on enhancing the upper critical magnetic field (Bc2). Ti is generally doped into Nb or Sn-alloys in practical Nb3Sn superconducting wires, and it would be preferable to add Ti to the Sn side from a manufacturing perspective. However, Ti-doping on Sn sites could form some undesirable stable compounds layers at the interface with Nb as a diffusion barrier for Sn during the Nb3Sn layer formation. It is challenging to find a new reaction route that destabilizes these compound layers in the Nb3Sn formation process, which is expected to cause a dramatic improvement in Sn diffusion when Ti is doped to the Sn core. Nevertheless, there are few studies that fundamentally investigate this aspect. Studies have reported that Zn is effective for promoting Nb3Sn layer formations. Therefore, in this study, specific diffusion couples of Nb/Cu/Sn were fabricated with different combinations of Ti and Zn doping to Cu and Sn and their diffusion reaction behaviors in Nb3Sn layer formation were investigated. Besides, anticipating a potential grain refinement effect, an Mg and Zn co-doped sample was additionally fabricated. However, the grain refinement by Mg was not seen in the present wire configuration. The effect of Zn addition on promoting the Nb3Sn layer formation appeared at 650 °C/150 h HT, while it was not visible well at 685 °C/100 h HT.
{"title":"Effect of Zn Addition on NbSn Layer Formation in the Nb/Cu-Sn-Ti Diffusion Reaction","authors":"Koki Asai;Tsuyoshi Yagai;Taku Moronaga;Nobuya Banno","doi":"10.1109/TASC.2025.3539271","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539271","url":null,"abstract":"Enhancing the characteristics of Nb<sub>3</sub>Sn superconducting wire is essential for the development of magnets for fusion reactors like ITER and DEMO. It has been established that Ti-doping has a significant effect on enhancing the upper critical magnetic field (<italic>B<sub>c2</sub></i>). Ti is generally doped into Nb or Sn-alloys in practical Nb<sub>3</sub>Sn superconducting wires, and it would be preferable to add Ti to the Sn side from a manufacturing perspective. However, Ti-doping on Sn sites could form some undesirable stable compounds layers at the interface with Nb as a diffusion barrier for Sn during the Nb<sub>3</sub>Sn layer formation. It is challenging to find a new reaction route that destabilizes these compound layers in the Nb<sub>3</sub>Sn formation process, which is expected to cause a dramatic improvement in Sn diffusion when Ti is doped to the Sn core. Nevertheless, there are few studies that fundamentally investigate this aspect. Studies have reported that Zn is effective for promoting Nb<sub>3</sub>Sn layer formations. Therefore, in this study, specific diffusion couples of Nb/Cu/Sn were fabricated with different combinations of Ti and Zn doping to Cu and Sn and their diffusion reaction behaviors in Nb<sub>3</sub>Sn layer formation were investigated. Besides, anticipating a potential grain refinement effect, an Mg and Zn co-doped sample was additionally fabricated. However, the grain refinement by Mg was not seen in the present wire configuration. The effect of Zn addition on promoting the Nb<sub>3</sub>Sn layer formation appeared at 650 °C/150 h HT, while it was not visible well at 685 °C/100 h HT.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1109/TASC.2025.3539257
Yi Li;Siwei Chen;Jonathan Dye;Piotr Bunkowski;Bruce Berlinger;Ryan Matthiessen;Yuhu Zhai
Rare-earth barium copper oxide (REBCO) high-temperature superconducting (HTS) magnets are considered a game changer for the capability of generating magnetic fields exceeding 20 T at or above liquid helium temperature, combined with the potential for substantially reduced manufacturing and operational costs. Princeton Plasma Physics Laboratory is dedicated to developing large-bore high-field superconducting magnet systems to support forefront physics research. Our current project focuses on a ${mathrm{phi }}$72-mm cold-bore REBCO insert comprising 21 dry-wound double-pancake coils, designed to generate at least 8 T when nested within a 12-T outsert magnet. A significant challenge for high-field REBCO magnets is the time-varying-magnetic-field-induced screening currents (SC) in the REBCO conductors, which can cause localized strain and stress concentrations. This paper presents a numerical study of the SC-induced strain in the REBCO insert magnet, confirming that the SC-induced strain can be substantially suppressed by energizing the REBCO insert before the outsert magnets. We discuss and reveal the mechanism behind this reduction. By applying this strategy, we expect to unleash the potential of the REBCO insert magnet to generate up to 12 T in a 12-T background field.
稀土钡铜氧化物（REBCO）高温超导（HTS）磁体能够在液氦温度或更高的温度下产生超过 20 T 的磁场，并具有大幅降低制造和运营成本的潜力，因此被认为是改变游戏规则的重要因素。普林斯顿等离子体物理实验室致力于开发大口径高磁场超导磁体系统，以支持前沿物理研究。我们目前的项目重点是一个 ${mathrm{phi }}$72 毫米的冷内孔 REBCO 插入件，它由 21 个干绕双饼线圈组成，当嵌套在一个 12 T 的外置磁体中时，可产生至少 8 T 的磁场。高磁场 REBCO 磁体面临的一个重大挑战是 REBCO 导体中由时变磁场引起的屏蔽电流 (SC)，它会导致局部应变和应力集中。本文对 REBCO 插入式磁体中 SC 诱导的应变进行了数值研究，结果证实，在外置磁体之前给 REBCO 插入式磁体通电，可以大大抑制 SC 诱导的应变。我们讨论并揭示了这种减少背后的机制。通过应用这一策略，我们有望释放 REBCO 插入式磁体的潜力，在 12 T 背景场中产生高达 12 T 的磁场。
{"title":"Suppressing Screening-Current-Induced Strain in a 72-mm-Bore REBCO Insert for a 20-T Magnet: A Numerical Study","authors":"Yi Li;Siwei Chen;Jonathan Dye;Piotr Bunkowski;Bruce Berlinger;Ryan Matthiessen;Yuhu Zhai","doi":"10.1109/TASC.2025.3539257","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539257","url":null,"abstract":"Rare-earth barium copper oxide (REBCO) high-temperature superconducting (HTS) magnets are considered a game changer for the capability of generating magnetic fields exceeding 20 T at or above liquid helium temperature, combined with the potential for substantially reduced manufacturing and operational costs. Princeton Plasma Physics Laboratory is dedicated to developing large-bore high-field superconducting magnet systems to support forefront physics research. Our current project focuses on a <inline-formula><tex-math>${mathrm{phi }}$</tex-math></inline-formula>72-mm cold-bore REBCO insert comprising 21 dry-wound double-pancake coils, designed to generate at least 8 T when nested within a 12-T outsert magnet. A significant challenge for high-field REBCO magnets is the time-varying-magnetic-field-induced screening currents (SC) in the REBCO conductors, which can cause localized strain and stress concentrations. This paper presents a numerical study of the SC-induced strain in the REBCO insert magnet, confirming that the SC-induced strain can be substantially suppressed by energizing the REBCO insert before the outsert magnets. We discuss and reveal the mechanism behind this reduction. By applying this strategy, we expect to unleash the potential of the REBCO insert magnet to generate up to 12 T in a 12-T background field.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1109/TASC.2025.3539265
Jiyoung Yoon;Jeongwoo Seo;Yoon Do Chung;Jae Young Jang;Young Jin Hwang
This article addresses the design, manufacturing, and testing of a contactless current charging system for high-temperature superconductor (HTS) coils. Traditional methods of charging HTS coils typically involve power-driven techniques, which result in a substantial thermal load due to thermal conduction. To mitigate this issue, we developed a system using an inductive coupling technique. The design of this system focuses on optimizing the magnetic coupling coefficient to ensure efficient power transfer to the HTS coils. Essential components, such as a magnetic coupler, a resonance circuit, and a rectifier, were designed and manufactured to match the operating environment of the HTS coil. A series of practical current charging tests were conducted to evaluate the feasibility of the system. The results from these tests confirmed the successful contactless charging of HTS coils, indicating the system's potential applicability in various HTS magnet applications.
{"title":"Development and Evaluation of an Inductive Coupling-Based Contactless Current Charging System for High-Temperature Superconductor Coils","authors":"Jiyoung Yoon;Jeongwoo Seo;Yoon Do Chung;Jae Young Jang;Young Jin Hwang","doi":"10.1109/TASC.2025.3539265","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539265","url":null,"abstract":"This article addresses the design, manufacturing, and testing of a contactless current charging system for high-temperature superconductor (HTS) coils. Traditional methods of charging HTS coils typically involve power-driven techniques, which result in a substantial thermal load due to thermal conduction. To mitigate this issue, we developed a system using an inductive coupling technique. The design of this system focuses on optimizing the magnetic coupling coefficient to ensure efficient power transfer to the HTS coils. Essential components, such as a magnetic coupler, a resonance circuit, and a rectifier, were designed and manufactured to match the operating environment of the HTS coil. A series of practical current charging tests were conducted to evaluate the feasibility of the system. The results from these tests confirmed the successful contactless charging of HTS coils, indicating the system's potential applicability in various HTS magnet applications.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1109/TASC.2025.3539267
Jun Ogawa;Satoshi Fukui;Yuto Yamada;Yohei Noguchi;Naoto Muramatsu;Kazuto Sugitsuma
High-temperature superconducting (HTS) tapes exhibit a flat plate structure. Experiments have shown the characteristics of pancake-type superconducting capacitor using HTS tapes as electrodes. This pancake-type HTS capacitor also functions as an inductance because it creates a self-magnetic field, and the inductance and capacitance facilitate the creation of an all-superconducting resonant circuit by itself. As AC loss in the HTS circuit is converted into a resistive component, it exerts a significant impact on the Q-factor characteristic, which is the evaluation standard for resonant circuits. Thus, evaluating AC loss characteristics is very important for designing fully superconducting resonant circuits. In this study, the current distribution is not uniform towing to the charge transfer between electrodes in the toroidal full-superconducting resonator; thus, the AC loss was derived in each part using the finite element method (FEM). FEM was employed to derive the AC loss and Q-factor. Considering the resistance component that exists due to the AC losses being nonlinear with respect to the current, a simple equivalent circuit was used to derive the Q-factor.
{"title":"Numerical Investigation of AC Losses in Toroidal Full-Superconducting Resonator Using ReBCO Tapes","authors":"Jun Ogawa;Satoshi Fukui;Yuto Yamada;Yohei Noguchi;Naoto Muramatsu;Kazuto Sugitsuma","doi":"10.1109/TASC.2025.3539267","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539267","url":null,"abstract":"High-temperature superconducting (HTS) tapes exhibit a flat plate structure. Experiments have shown the characteristics of pancake-type superconducting capacitor using HTS tapes as electrodes. This pancake-type HTS capacitor also functions as an inductance because it creates a self-magnetic field, and the inductance and capacitance facilitate the creation of an all-superconducting resonant circuit by itself. As AC loss in the HTS circuit is converted into a resistive component, it exerts a significant impact on the Q-factor characteristic, which is the evaluation standard for resonant circuits. Thus, evaluating AC loss characteristics is very important for designing fully superconducting resonant circuits. In this study, the current distribution is not uniform towing to the charge transfer between electrodes in the toroidal full-superconducting resonator; thus, the AC loss was derived in each part using the finite element method (FEM). FEM was employed to derive the AC loss and Q-factor. Considering the resistance component that exists due to the AC losses being nonlinear with respect to the current, a simple equivalent circuit was used to derive the Q-factor.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-4"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-05DOI: 10.1109/TASC.2025.3538574
K. Shiohara;M. Sato;Y. Takahashi;K. Adachi;A. Kawagoe;T. Izumi;M. Iwakuma
In order to achieve a decarbonized society, aircraft must be equipped with electric propulsion systems. To achieve this, it is essential to reduce the overall weight of the electrical components. Therefore, one of the solutions to achieve this content is to apply superconducting technology to the propulsion system. In this case, superconducting coated conductors made of REBa2Cu3Oy, where RE represents a rare-earth element (yttrium, gadolinium, etc.), can considerably enhance the performance of the motors, generators, transformers, and cables. Previous studies conducted direct-current (DC) and alternating-current (AC) carrying tests on the cable conductors and cable terminations of stacked superconducting cables (which were designed to be compact and lightweight via opting for short-length specimens), respectively. Based on these studies, further weight reduction (less than 1 kg/kA/m) and evaluation of the cable system are necessary when considering its installation in an aircraft. Herein, a 15-m-class stacked superconducting cable and cable terminations are connected as a cable system to implement DC and AC current-carrying tests. To make the cable lighter, metallic corrugated tubes accounting for a large proportion of weight of the conventional superconducting cable structure are replaced with resin corrugated tubes. In this form, the 1110 Arms of current-carrying characteristics required for the 1 MW class were verified.
{"title":"Stacked Superconducting Cables With Coated Conductors Using New Corrugated Tubes for Electric Propulsion Systems for Aircraft","authors":"K. Shiohara;M. Sato;Y. Takahashi;K. Adachi;A. Kawagoe;T. Izumi;M. Iwakuma","doi":"10.1109/TASC.2025.3538574","DOIUrl":"https://doi.org/10.1109/TASC.2025.3538574","url":null,"abstract":"In order to achieve a decarbonized society, aircraft must be equipped with electric propulsion systems. To achieve this, it is essential to reduce the overall weight of the electrical components. Therefore, one of the solutions to achieve this content is to apply superconducting technology to the propulsion system. In this case, superconducting coated conductors made of REBa<sub>2</sub>Cu<sub>3</sub>O<italic><sub>y</sub></i>, where RE represents a rare-earth element (yttrium, gadolinium, etc.), can considerably enhance the performance of the motors, generators, transformers, and cables. Previous studies conducted direct-current (DC) and alternating-current (AC) carrying tests on the cable conductors and cable terminations of stacked superconducting cables (which were designed to be compact and lightweight via opting for short-length specimens), respectively. Based on these studies, further weight reduction (less than 1 kg/kA/m) and evaluation of the cable system are necessary when considering its installation in an aircraft. Herein, a 15-m-class stacked superconducting cable and cable terminations are connected as a cable system to implement DC and AC current-carrying tests. To make the cable lighter, metallic corrugated tubes accounting for a large proportion of weight of the conventional superconducting cable structure are replaced with resin corrugated tubes. In this form, the 1110 A<sub>rms</sub> of current-carrying characteristics required for the 1 MW class were verified.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-4"},"PeriodicalIF":1.7,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A simple method is proposed for the establishment of resistance-controlled (RC) interfaces to control bypass resistance inside windings for no-insulation (NI) scheme coils. The method uses stainless steel mesh impregnated with epoxy to create current bypass paths between REBCO tape turns or between a REBCO tape turn and a copper sheet. Short samples for an RC interface are evaluated for bypass resistance using the four-terminal method at 77 K. Each sample is composed of two REBCO tapes between which a 30 μm-thick SS mesh which is impregnated with epoxy to keep the contacts between the surfaces of the REBCO tapes and SS mesh. Most samples show bypass resistances of the order of 100–1000 mΩ·cm2; such high values are of importance from the viewpoint of achieving self-protection of NI scheme coils, via management of both overheating and overstressing. Issues related to variations in bypass resistances must be addressed before the proposed method can be implemented in coils.
{"title":"Resistance-Controlled (RC) Interface With Metal Mesh for Managing Current Bypassing in No-Insulation (NI) Scheme Coils","authors":"Mizuho Kawahata;Yuya Tanaka;Yu Suetomi;Syouon Imanishi;Kazuya Nakamura;Tomoaki Takao;Renzhong Piao;Kensuke Kobayashi;Toshio Yamazaki;Yoshinori Yanagisawa","doi":"10.1109/TASC.2025.3538672","DOIUrl":"https://doi.org/10.1109/TASC.2025.3538672","url":null,"abstract":"A simple method is proposed for the establishment of resistance-controlled (RC) interfaces to control bypass resistance inside windings for no-insulation (NI) scheme coils. The method uses stainless steel mesh impregnated with epoxy to create current bypass paths between REBCO tape turns or between a REBCO tape turn and a copper sheet. Short samples for an RC interface are evaluated for bypass resistance using the four-terminal method at 77 K. Each sample is composed of two REBCO tapes between which a 30 μm-thick SS mesh which is impregnated with epoxy to keep the contacts between the surfaces of the REBCO tapes and SS mesh. Most samples show bypass resistances of the order of 100–1000 mΩ·cm<sup>2</sup>; such high values are of importance from the viewpoint of achieving self-protection of NI scheme coils, via management of both overheating and overstressing. Issues related to variations in bypass resistances must be addressed before the proposed method can be implemented in coils.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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