Operational characteristics of a flux pump

Mawardi, Osman K.; Gattozzi, Angelo L.; Chung, H.

doi:10.1109/tmag.1979.1060045

Cited by 12 publications

(5 citation statements)

References 6 publications

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“…Voc is proportional to the rate at which flux cuts the HTS stator, which is determined by the rotational speed of the flux pump rotor. The superconducting coil has an inductance, L, and the governing equation for the circuit is, (1) where the total resistance is given by R = Rc + Rd, with Rc denoting the contact resistance of soldered joints within the HTS circuit, and Rd denoting the dynamic resistance experienced at the flux pump stator, can be expressed as [10,12,18], (2) where 2a is the width of the stator CC and l is the interaction length of the AC magnetic field with the conductor. Ic0 and B0 are parameters from the Kim model [20] for critical current,…”

Section: Fig 2 Herementioning

confidence: 99%

“…uperconducting flux pump devices enable large-currents to be injected into a superconducting coil, without the requirement for current leads which bridge between room temperature and the cryogenic environment [1][2][3][4][5][6][7][8][9][10][11][12]. As such, an efficient high-Tc superconducting (HTS) flux pump could substantially reduce the cryogenic heat load incurred when operating HTS coils and magnets.…”

Section: Introductionmentioning

confidence: 99%

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A Novel Rotating HTS Flux Pump Incorporating a Ferromagnetic Circuit

Jiang

Bumby

Badcock

et al. 2016

IEEE Trans. Appl. Supercond.

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High Temperature Superconductor (HTS) flux pumps enable large currents to be injected into a superconducting coil without requiring normal-conducting current leads. We present results from an experimental axial-type HTS rotating flux pump which employs a ferromagnetic circuit to focus incident flux upon a coated-conductor (CC) stator wire. We show that this device can inject currents of > 50 A into an HTS coil at 77 K, and is capable of operating at flux gaps greater than 18 mm. Accommodating a cryostat wall within this flux gap will enable future flux pump designs, in which all moving parts are located outside the cryostat.

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Section: Fig 2 Herementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Novel Rotating HTS Flux Pump Incorporating a Ferromagnetic Circuit

Jiang

Bumby

Badcock

et al. 2016

IEEE Trans. Appl. Supercond.

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show abstract

“…A more accurate solution for the magnetic field in a normal region was computed (8) and the result is shown in graphical form in Fig. 5.…”

Section: Bo(mentioning

confidence: 99%

Brushless Superconducting Generator.

Mawardi¹,

Ferendeci²

1982

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“…A complete circuit connection is formed between stator and the load via wires. The LTS FP operates on the principle of increasing the total ux in the superconducting loop [39,23,2]. This can be understood by considering a simplied version of FP consisting of a LTS thin sheet (stator) connected to the load via superconducting leads.…”

Section: Lts Flux Pumpmentioning

confidence: 99%

Current-pumping performance of axial-symmetric superconducting dynamo designs

Phang¹

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<p>In this project, the current pumping performances of three high temperature superconducting (HTS) dynamos (mechanically-rotating flux pumps) were investigated. These flux pumps (FPs) were identified as the Gen 1, Gen 2 and Gen 4 FP respectively. They were modelled using simple DC equivalent circuits and their performances were defined by three output parameters: DC open-circuit voltage (Voc), dynamic resistance (Rd) and DC short-circuit current (Isc). The experimental results showed that these FPs produced non-zero DC output voltages across their stators and each supplied DC output currents into series connected superconducting circuits. The Gen 1 FP was cooled with liquid nitrogen and operated at 77 K. The stators were made from 12-mm wide copper-coated yttrium barium copper oxide (YBCO) HTS conductors. The objective of the experiment was to investigate the effect of the rotor magnet size, geometry and orientation (with respect to the stators) on the FP performance. The design parameters, based on the width and the length of the magnet with respect to the stator, for optimal FP performance were determined. The Gen 2 FP was also cooled with liquid nitrogen and operated at 77 K. The stators were made from 46-mm wide Ag-coated YBCO HTS conductors. The objective of the experiment was to investigate the effect of stator width on the FP performance at various magnet frequencies. This was done by slitting two of the stators to form parallel stators with equal width, but smaller than the original conductor width. The experimental results showed that the FP performance was highly dependent on the operating frequency. Three operating frequency regimes were observed: low, mid and high. At high frequency, the Voc decreased and the Rd increased signifcantly. This was attributed to the local heating effect in the stator due to the increase in the current density. As a result, the FP produced zero output current in this regime. The AC voltage waveforms measured across the stators in different frequency regimes were very different in shapes and amplitudes. Therefore, these waveforms can be used to identify the operating frequency regime of the FP. At some operating frequencies in the mid frequency regime, bi-stable operating modes were observed, each mode resulted in different output parameters. The Gen 4 FP was constructed in this project. It was cooled via thermal conduction method using a cryorefrigerator system. It had an axial-symmetric stator design where the shape of the stator is cylindrical. The width of the stator was considerably larger compared with the Gen 1 and Gen 2 FPs. The experiment objective was to investigate whether this design would produce a DC current, and then characterise the FP performance at different operating temperatures. The experimental results showed that the time-averaged DC output voltage of the Gen 4 FP was much higher compared with the Gen 1 and Gen 2 FPs. The reason is that it produced a DC output voltage for almost the entire rotor cycle. The experimental results also indicated that the Gen 4 FP has the capability to produce output currents in the kA range.</p>

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Operational characteristics of a flux pump

Cited by 12 publications

References 6 publications

A Novel Rotating HTS Flux Pump Incorporating a Ferromagnetic Circuit

A Novel Rotating HTS Flux Pump Incorporating a Ferromagnetic Circuit

Brushless Superconducting Generator.

Current-pumping performance of axial-symmetric superconducting dynamo designs

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