Improving the Central Magnetic Field of an HTS Magnet Using Multiple Flux Pumps

Wei, Jiafu; Wang, Wei; Li, Zhou; Zhang, Chenyan; Wang, Xueqing; Yang, Zhenxuan; Xiong, Chenling; Yang, Chao; Long, Run; Yang, Zhixing; Li, Hong; Xu, Hang; Zhu, Yingwei; Lei, Yong

doi:10.1109/tasc.2022.3158323

Cited by 4 publications

(2 citation statements)

References 30 publications

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“…Recently, HTS flux pumps have received a lot of attention, such as transformer-rectifier flux pumps [13][14][15][16][17] and traveling wave flux pumps [18]. At present, there are several types of travelling wave flux pumps, mainly including thermally actuated flux pumps [19][20][21], HTS dynamo flux pumps [22][23][24][25][26][27], linear-motor type flux pumps [28][29][30][31], pulsetype flux pumps [32,33] and linear flux pumps [34,35]. Increasing the charging current is a major task in flux pump research.…”

Section: Introductionmentioning

confidence: 99%

Miniaturized HTS linear flux pump with a charging capability of 120 A

Chen

et al. 2023

Supercond. Sci. Technol.

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Owing to the presence of joint resistance and flux creep, high-temperature superconducting (HTS) coils without a power supply inevitably suffer from current decay. A flux pump is a voltage supply that requires connections with smaller footprints and a lower heat load than traditional current leads. In this study, we explain the principle of the upper limit for the output current of the traveling wave flux pumps. Based on this principle, a miniaturized linear flux pump device was developed. With narrow and misaligned iron teeth, elaborate 3D geometry of the iron pieces, and optimized driving current waveform, the miniaturized flux pump can support more than 120 A output current with only a 10 mm wide HTS tape and a compact size of 4.6 × 4.6 × 3.4 cm. Our experimental results show that the critical current of the HTS tape has a significant effect on the flux pump output. An HTS tape with a larger critical current supports a higher maximum transport current, whereas an HTS tape with a smaller critical current requires less applied current for positive output. Finally, excitation tests on HTS coils were performed. Charge/active discharge and field supplement experiments were done on a maglev HTS racetrack coil of 0.4 H, where charging/field supplement capbility of the miniaturized flux pump were demonstrated up to 46.8 A (close to the critical current of the coil). It has also been proved that the flux pump can work together with an external power supply with persistent current switch. The miniaturized flux pump can also independently charge an HTS coil of 60 μH to 91.6 A, which is the critical current of the coil at a low voltage criterion.

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Section: Introductionmentioning

confidence: 99%

Miniaturized HTS linear flux pump with a charging capability of 120 A

Chen

et al. 2023

Supercond. Sci. Technol.

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“…Rice et al estimated a potential reduction of 90% and 98% in the cryogenic load for charging and maintaining 60 kA into the toroidal field coils of fusion magnets, proving to be a massive space saver as well [31]. Flux pumps could also bring benefits to the biomedical industry, in fact, Wang et al designed and constructed a compact 1.5 T HTS MRI system dedicated for human joint diagnosis [32,33], whilst Coombs et al are constructing a portable MRI for human head scanning that employs a flux pump [34].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Performance of Commercial High Temperature Superconducting Tapes for Dynamo Flux Pump Applications

Russo,

Morandi

2023

Energies

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High Temperature Superconducting (HTS) dynamo flux pumps are a promising alternative to metal current leads for energization and the persistent current mode operation of high current DC superconducting magnet systems for applications in rotating machines, such as Magnetic Resonance Imaging (MRI) or fusion systems. The viability of the flux pump concept has been widely proven by laboratory experiments and research is now in progress for the design and optimization of flux pump devices for practical applications. It has been widely established that the dependence of the critical current density (Jc) on the temperature (T), the magnetic field magnitude (B), and the orientation (θ), has a substantial impact on the overall DC voltage obtained at the terminals, as well as on the current limit and the loss of the flux pump. Since HTS tapes produced by different manufacturers, they show different dependencies of Jc with the amplitude and the orientation of the magnetic field. They also give rise to different outputs when employed in flux pumps. In this paper, we evaluate and compare the performance of several commercial HTS tapes used for flux pumping purposes through numerical simulation. We also investigate the dependence of the flux pump ‘s performance on the operating temperatures. A 2D finite element numerical model is first developed and validated against experimental data at 77 K. Afterward, the same HTS dynamo apparatus used for validation is exploited for the comparison. The Jc(B,θ,T) and n(B,θ,T) relations, which characterize each different tape in the model, are reconstructed via artificial intelligence techniques based on the open-access database of the Robinson Research Institute. It is shown in the paper that certain tapes are more suitable than others for flux pump applications and that the best overall operating temperature is in the vicinity of 77 K.

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