Field Measurement and Analysis of a 3 T 66 mm No-Insulation HTS NMR Magnet With Screening Current and Manufacturing Uncertainty Considered

Bang, Jeseok; Kim, Seokho; Jang, Jae Young; Hwang, Young Jin; Cho, Mincheol; Kim, Jaemin; Lee, Jung Tae; Ahn, Min Cheol; Lee, SangGap; Hahn, Seungyong

doi:10.1109/tasc.2019.2898005

Cited by 16 publications

(5 citation statements)

References 38 publications

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“…Unlike other HTS rotating machines, since the HTS field coil is fixed, the mechanical stability is high, and the excitation and cooling structure of the HTS coil can be simplified. The mechanical stability of the fixed-operated NI HTS coil has already been confirmed through a long-term operation test of the NI HTS magnet for NMR [2].…”

Section: Introductionmentioning

confidence: 84%

“…High-temperature superconducting (HTS) wires have excellent critical current and mechanical properties, making them suitable materials for high magnetic field applications. Thus, many studies are being carried out to apply high magnetic field coils made of HTS wires to electrical machines such as motors and generators as well as analytical equipment such as NMR and MRI [1,2]. Among them, motors and generators to which HTS coils are applied can have high output power density, so they are considered as one of the promising future electrical machines.…”

Section: Introductionmentioning

confidence: 99%

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Design and Characteristic Analysis of a Homopolar Synchronous Machine Using a NI HTS Field Coil

Hwang

2021

Energies

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This paper deals with a homopolar synchronous machine (HSM) applying high-temperature superconducting (HTS) field coils. Superconductors, especially high-temperature superconductors, have high potential as advanced materials for next-generation electrical machines due to their high critical current density and excellent mechanical strength. However, coils made with high-temperature superconductors have a high risk of being damaged in the event of a quench due to the intrinsic low normal zone propagation velocity (NZPV). Therefore, the coil protection issue has been regarded as one of the most important research fields in HTS coil applications. Currently, the most actively studied method for quench protection of the HTS coils is the no-insulation (NI) winding technique. The NI winding technique is a method of winding an HTS coil without inserting an insulating material between turns. This method can automatically bypass the current to the adjacent turn when a local quench occurs inside the HTS coil, greatly improving the operating stability of the HTS coils. Accordingly, many institutions are conducting research to develop advanced electrical machines using NI HTS coils. However, the NI HTS coil has its intrinsic charge/discharge delay problem, which makes it difficult to successfully develop electrical machines using the NI HTS coil. In this study, we investigated how this charging/discharging problem appeared when the NI HTS coil was used in an HTS homopolar synchronous machine (HSM) which is one of the electrical machines with a high possibility of applying the HTS coil in the future because it has a stationary field coil structure. For this, the characteristic resistances of HTS coils were experimentally obtained and applied to the simulation model.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Design and Characteristic Analysis of a Homopolar Synchronous Machine Using a NI HTS Field Coil

Hwang

2021

Energies

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“…l i is the length of the REBCO tape used in the ith element, and l di is the averaged size of the defect in the ith element expressed with w t and w h identified in lengthwise I c (x) measurement in figure 3. n is the index value of the superconductor and a value of 20 is employed [13,26]. To consider the temperature change of copper current lead observed during the tests, temperature dependencies of R ci (T) and I ci (T) were considered.…”

Section: Effect Of 'Defect' On Coil Performance Analyzed By Equivalen...mentioning

confidence: 99%

“…A decade of progress in the no-insulation (NI) high-temperature superconducting (HTS) magnet technology [1][2][3][4][5][6][7][8][9][10] has broaden its applications beyond science laboratory magnets [11][12][13][14][15][16][17][18] to industrial ones [19][20][21]. Some industrial applications often require a marginal field strength of ∼5 T or even lower [19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

‘Defect-irrelevant-winding’ no-insulation (RE)Ba₂Cu₃O_7 − x pancake coil in conduction-cooling operation

Bong

Kim

Bang

et al. 2021

Supercond. Sci. Technol.

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This paper reports experiment and simulation results of a ‘defect-irrelevant-winding (DIW)’ no-insulation (NI) (RE)Ba2Cu3O7 − x pancake coil operated in a conduction-cooling environment at temperatures lower than 77 K. The key idea of the DIW high-temperature superconductor (HTS) winding technique, firstly proposed in 2016, is to wind an NI pancake coil with HTS tapes, on purpose, containing multiple ‘defects.’ Using the defect (flawed) HTS tapes, we expect to significantly lower the construction cost of a DIW HTS magnet in marginal sacrifice of the magnet performance. In this study, charging tests of a DIW coil were performed in a conduction cooling system by controlling the temperature of the second stage in a range of 20–65 K, to determine the maximum operable current that avoids thermal runaway of the test coil at a given temperature. Coil terminal voltages, center fields, local temperatures, and power supply currents were carefully monitored during the tests, and the trend for each parameter was obtained. Also, by use of an equivalent circuit model, the test results were numerically analyzed to evaluate the effect of local defects on the overall performance of the test coil in order to validate the feasibility of the DIW HTS coil in operation under the conduction-cooling environment at temperatures lower than 77 K.

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“…Unlike other coil shapes, such as solenoid [20][21][22][23][24] or racetrack types [25][26][27][28], there have not been many cases of saddle-shaped coils with the no-insulation (NI) technique incorporated [29]. Since particle accelerators with LTS or HTS dipole magnets have presented an important role in scientific discoveries [30][31][32], the demand for high-field accelerators has existed for decades.…”

Section: Introductionmentioning

confidence: 99%

Investigation on nonuniform current density and shape deformation affecting the magnetic field performance of a saddle-shaped no-insulation HTS cosine–theta dipole magnet

Kim

Park

Bang

et al. 2023

Supercond. Sci. Technol.

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In particle accelerators, high magnetic fields are desirable for discovering new particles. Dipole magnets using superconductors have played a key role in creating required field intensity and uniformity. In contrast, high temperature superconductor (HTS) dipole magnets have recently been spotlighted because of their ability to generate higher magnetic fields compared to their low temperature superconductor counterpart. Similar needs have emerged in other fields using magnets, and no-insulation (NI) technology is considered a feasible option to reach high magnetic fields by overcoming the disadvantages of HTS magnets. However, research has rarely been carried out on the utilization of NI HTS magnet technology for dipole magnets in high-field accelerators. Here we show the design, fabrication, and test results of an NI HTS dipole magnet with numerical analysis results. This paper aims to investigate the effect of nonuniform current density and undesirable shape deformation on the magnetic field distribution of a saddle-shaped NI HTS dipole magnet. The magnet is designed and constructed considering the 'constant perimeter winding' technique and tested in liquid nitrogen. The field mapping process is also performed along a designated mapping trajectory to obtain a magnetic field distribution. T-A formulation-based simulation model, named 'sequential simulation model,' is suggested to reproduce measurements and employed considering current distribution and shape deformation. As a result of quantitative analysis of the transverse direction measurement results, the magnetic field error decreased by 0.02 percent point (pp) when the nonuniform current density is considered. It decreased by 0.13 pp when the shape deformation is considered. Moreover, the critical current calculated through additional numerical analysis shows an error of up to 10%. In conclusion, the saddle-shaped NI HTS dipole magnet can produce a sufficient magnetic field level for particle accelerator research, even though the field distribution shows a uniformity of 0.37% within this study.

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Field Measurement and Analysis of a 3 T 66 mm No-Insulation HTS NMR Magnet With Screening Current and Manufacturing Uncertainty Considered

Cited by 16 publications

References 38 publications

Design and Characteristic Analysis of a Homopolar Synchronous Machine Using a NI HTS Field Coil

Design and Characteristic Analysis of a Homopolar Synchronous Machine Using a NI HTS Field Coil

‘Defect-irrelevant-winding’ no-insulation (RE)Ba₂Cu₃O_7 − x pancake coil in conduction-cooling operation

Investigation on nonuniform current density and shape deformation affecting the magnetic field performance of a saddle-shaped no-insulation HTS cosine–theta dipole magnet

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Field Measurement and Analysis of a 3 T 66 mm No-Insulation HTS NMR Magnet With Screening Current and Manufacturing Uncertainty Considered

Cited by 16 publications

References 38 publications

Design and Characteristic Analysis of a Homopolar Synchronous Machine Using a NI HTS Field Coil

Design and Characteristic Analysis of a Homopolar Synchronous Machine Using a NI HTS Field Coil

‘Defect-irrelevant-winding’ no-insulation (RE)Ba2Cu3O7 − x pancake coil in conduction-cooling operation

Investigation on nonuniform current density and shape deformation affecting the magnetic field performance of a saddle-shaped no-insulation HTS cosine–theta dipole magnet

Contact Info

Product

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‘Defect-irrelevant-winding’ no-insulation (RE)Ba₂Cu₃O_7 − x pancake coil in conduction-cooling operation