An Integrated Coil Form Test Coil Design for High Current REBCO DC Solenoids

Painter, T.A.; Abraimov, D.; Bole, S.; Coombs, Thomas; Coombs, Timothy A.; Francis, A; Geng, Jianzhao; Larbalestier, D. C.; Sossong, Dominick; Viouchkov, Y.; Voran, A. J.; White, Mike

doi:10.1109/tasc.2019.2899146

Cited by 6 publications

(4 citation statements)

References 9 publications

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“…For a given coil application requiring a fixed number of ampere-turns, increasing the operating current will significantly reduce the coil inductance (as the inductance of a coil is approximately proportional to the square of the number of turns). This is desirable in terms of reducing both the ramping voltage and size of the magnet [10]. It has also been shown that high-current-capacity no-insulation (NI) coils wound from multiple parallel CCs can substantially reduce the charging delay for NI magnets [11].…”

Section: Introductionmentioning

confidence: 99%

Maximising the current output from a self-switching kA-class rectifier flux pump

Geng

Bumby

Badcock

2020

Supercond. Sci. Technol.

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High current operation of HTS magnets is desirable for many applications, but operating currents are typically limited by resistive heating of the normal-conducting current leads, which connect the cryogenic magnet coil to a room-temperature electronic power supply. Rectifying flux pumps are a feasible alternative solution as they enable current to be directly injected into the HTS magnet coil via a closed superconducting circuit. In this work, we have developed and demonstrated two prototype HTS self-rectifying flux pump devices capable of delivering very high output currents. One of these devices can deliver a maximum direct current of >2 kA. This is a new record for the flux pump excitation of an HTS coil. Unlike other rectifying flux pumps, the self-rectifying flux pumps reported here do not employ an active switching component. Instead passive 'self-switching' rectification is achieved by applying an assymmetric current waveform to the primary winding. This significantly reduces the complexity of the system compared to other flux pump architectures, and removes the need for dissipative electronic components within the cryogenic environment. We demonstrate that these devices also function when the iron core linking the superconducting secondary and the normal conducting primary is broken by a pair of air gaps. In these conditions DC currents of >600 A can be maintained with a total air gap length of 10 mm. This indicates that this approach represents a feasible practical solution for through-wall excitation of high current HTS magnets.

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Section: Introductionmentioning

confidence: 99%

Maximising the current output from a self-switching kA-class rectifier flux pump

Geng

Bumby

Badcock

2020

Supercond. Sci. Technol.

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“…(2) Winding an individual coil and jointing coils together could be more difficult. This will need further investigation, yet the research from the NHMFL has shown the feasibility of a coil former for parallel layer-wound solenoids [36], which could work for co-wound pancake coils.…”

Section: Discussionmentioning

confidence: 99%

A parallel co-wound no-insulation REBCO pancake coil for improving charging delays

Geng

Zhang

2019

Supercond. Sci. Technol.

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High-T c superconducting coils wound by REBCO coated conductors with no turn-to-turn insulation have been widely used for high-field DC magnets, due to the fact that they have a higher engineering current density and can be self-protective during a quench. One long-lasting problem of no-insulation (NI) coils is the charging delay due to low characteristic resistance. In this paper, the authors propose the structure of a parallel co-wound NI pancake coil. Unlike a traditional NI pancake coil which is wound by a single tape, in the new design multiple NI tapes are co-wound. From a circuit point of view, the tapes are connected in parallel. It is discovered that the charging delay of the NI coil can be substantially reduced by the parallel co-wound method. The mechanism is that the inductance of a coil is proportional to the square of the number turns which is inversely proportional to the number of co-wound layers, whereas the characteristic resistance is nearly irrelevant to the number of layers, therefore the coil's time constant can be considerably reduced. The new design could also further increase the engineering current density of a magnet due to the independent current transporting of co-wound layers, which will be investigated in future work.

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“…There are strong interests in continuing the development of these REBCO cables for both nuclear fusion and particle accelerator magnet applications [5], [6]. In addition, a new concept of the so-called integrated-coil-form magnet was recently proposed based on a conductor with multiple simply stacked REBCO tapes [7].…”

Section: Introductionmentioning

confidence: 99%

Critical Current Measurement of REBCO Cables by Using a Superconducting Transformer

Lü

Weiss

et al. 2022

IEEE Trans. Appl. Supercond.

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Development of REBCO cables that carry high electrical current in high magnetic field is crucial for future large-scale magnet applications. This experimental work presents the critical current measurements of two different REBCO cables by a test facility at the National High Magnetic Field Laboratory (NHMFL). The simple-stacked cable is made by the NHMFL by stacking 21 REBCO tapes without soldering. The Conductor-on-Round-Core (CORC ® ) cable provided by Advanced Conductor Technologies has 21 layers of REBCO tapes with 2 tapes/layer. The test facility consists of a 12 T split solenoid magnet with 15 cm bore providing transverse field to the samples, a superconducting transformer (SCT) as a current source providing up to 45 kA current. Special attentions were paid to fabrication of solder joints between REBCO cables and the SCT output. The voltage-current traces were measured as a function of magnetic field at 4.2 K, from which the critical currents are determined. The details of this measurement are discussed.

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An Integrated Coil Form Test Coil Design for High Current REBCO DC Solenoids

Cited by 6 publications

References 9 publications

Maximising the current output from a self-switching kA-class rectifier flux pump

Maximising the current output from a self-switching kA-class rectifier flux pump

A parallel co-wound no-insulation REBCO pancake coil for improving charging delays

Critical Current Measurement of REBCO Cables by Using a Superconducting Transformer

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