Design Consideration and Conductor Selection of a Low AC Loss HTS REBCO Magnet Carrying High Currents at 20 K and 40 K

AC loss in high temperature superconductor coils have been frequently studied, however, mostly for AC power applications at 77 K, rather than specifically for high current but low frequency AC superconducting magnet at 20–40 K. Due to their easy operation and Helium shortage, more HTS magnet systems employ conduction-cooling with cryocoolers. The HTS magnets are known for high stability and likely tolerate high AC loss, but it is unclear what is the maximum AC frequency assuming that cryocooler has limited capability (a few hundred Watts) for the 20-40 K temperature range. This paper will specifically study AC loss in a simple HTS dipole but with three conductor/cable options using simulations, (1) 12 mm wide tape, (2) two parallel 6 mm wide tapes, and (3) 6/2 (six 2 mm strands) Roebel cables. It has been found that the magnet at 5 Hz generates 200–400 W AC loss at 20 K or 40 K, potentially be cooled by two single stage cryocoolers. The 6/2 Roebel cable based magnet may allow higher frequency (6–8 Hz) due to its transposition and narrower conductor width.

[1]  E. Pardo,et al.  Measurement of AC loss down to 25 K in a REBCO racetrack coil for electrical aircraft motor , 2022, Scientific Reports.

[2]  R. Badcock,et al.  Optimizing coil configurations for AC loss reduction in REBCO HTS fast-ramping magnets at cryogenic temperatures , 2022, Superconductivity.

[3]  Y. Zhai,et al.  A cryostat for a 6 T conduction-cooled, no-insulation multi-pancake HTS solenoid , 2022, IOP Conference Series: Materials Science and Engineering.

[4]  C. Macpherson,et al.  The principles of helium exploration , 2022, Petroleum Geoscience.

[5]  V. Shiltsev,et al.  Record High Ramping Rates in HTS Based Superconducting Accelerator Magnet , 2021, IEEE Transactions on Applied Superconductivity.

[6]  Jianhua Liu,et al.  Conduction-Coolled HTS Magnets Closed-Loop System Excited by a Rotating Magnets Flux Pump , 2022, IEEE Transactions on Applied Superconductivity.

[7]  B. Shen,et al.  Conceptual Design and Optimisation of HTS Roebel Tapes , 2022, IEEE Transactions on Applied Superconductivity.

[8]  W. T. B. de Sousa,et al.  Optimized Shape of Short-Circuited HTS Coils by Cutting Process for Superconducting Fault Current Limiters , 2021, IEEE Transactions on Applied Superconductivity.

[9]  P. Ribani,et al.  AC Losses in the First ITER CS Module Tests: Experimental Results and Comparison to Analytical Models , 2021, IEEE Transactions on Applied Superconductivity.

[10]  R. Badcock,et al.  15% reduction in AC loss of a 3-phase 1 MVA HTS transformer by exploiting asymmetric conductor critical current , 2021 .

[11]  R. Badcock,et al.  AC Loss Calculation on a 6.5 MVA/25 kV HTS Traction Transformer With Hybrid Winding Structure , 2020, IEEE Transactions on Applied Superconductivity.

[12]  Min Zhang,et al.  Fully superconducting machine for electric aircraft propulsion: study of AC loss for HTS stator , 2019, Superconductor Science and Technology.

[13]  F. Grilli,et al.  Non-twisted stacks of coated conductors for magnets: Analysis of inductance and AC losses , 2019, Cryogenics.

[14]  Francesco Grilli,et al.  Review of the AC loss computation for HTS using H formulation , 2019, Superconductor Science and Technology.

[15]  R. Badcock,et al.  Exploiting asymmetric wire critical current for the reduction of AC loss in HTS coil windings , 2019, Journal of Physics Communications.

[16]  Liwei Jing,et al.  Experimental and numerical study of the frequency-dependent transport ac losses of the YBa2Cu3O7−δ coil with and without flux diverters , 2019, Superconductor Science and Technology.

[17]  V. Shiltsev,et al.  Record fast-cycling accelerator magnet based on HTS conductor , 2019, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.

[18]  Zhenan Jiang,et al.  AC Loss Measurement in HTS Coil Windings Coupled With Iron Core , 2019, IEEE Transactions on Applied Superconductivity.

[19]  Wenjuan Song,et al.  AC loss simulation in a HTS 3-Phase 1 MVA transformer using H formulation , 2018, Cryogenics.

[20]  L. Bottura,et al.  Performance and Quench Characteristics of a Pancake Coil Wound With the 2G YBCO Roebel Cable , 2018, IEEE Transactions on Applied Superconductivity.

[21]  J. W. Jansen,et al.  AC losses in HTS coils for high-frequency and non-sinusoidal currents , 2017 .

[22]  R. Badcock,et al.  AC Loss Measurements in a Hybrid REBCO/BSCCO Coil Assembly , 2017, IEEE Transactions on Applied Superconductivity.

[23]  Seokho Kim,et al.  Performance of the Fast-Ramping High Temperature Superconducting Magnet System for an Active Magnetic Regenerator , 2017, IEEE Transactions on Applied Superconductivity.

[24]  R. Badcock,et al.  AC loss measurements in HTS coil assemblies with hybrid coil structures , 2016 .

[25]  Janina Decker,et al.  Case Studies In Superconducting Magnets Design And Operational Issues , 2016 .

[26]  Min Zhang,et al.  Total AC loss study of 2G HTS coils for fully HTS machine applications , 2015 .

[27]  M. Takahashi,et al.  AC Losses of an HTS Insert in a 25-T Cryogen-Free Superconducting Magnet , 2015, IEEE Transactions on Applied Superconductivity.

[28]  Kenji Tasaki,et al.  Design of Conduction-cooled HTS Coils for a Rotating Gantry , 2015 .

[29]  Hideaki Maeda,et al.  Recent Developments in High-Temperature Superconducting Magnet Technology (Review) , 2014, IEEE Transactions on Applied Superconductivity.

[30]  Takashi Komeda,et al.  Alternating current loss characteristics of a Roebel cable consisting of coated conductors and a three-dimensional structure , 2014 .

[31]  Victor M. R. Zermeno,et al.  3D modeling and simulation of 2G HTS stacks and coils , 2013, 1311.3580.

[32]  C. Kim,et al.  Electrical measurements of AC losses in high temperature superconducting coils at variable temperatures , 2013 .

[33]  W. Goldacker,et al.  AC Losses of Pancake Coils Made of Roebel Cable , 2013, IEEE Transactions on Applied Superconductivity.

[34]  M. Pekarčíková,et al.  AC Loss in Pancake Coil Made From 12 mm Wide REBCO Tape , 2013, IEEE Transactions on Applied Superconductivity.

[35]  Weijia Yuan,et al.  Numerical Analysis of AC Loss Reduction in HTS Superconducting Coils Using Magnetic Materials to Divert Flux , 2013, IEEE Transactions on Applied Superconductivity.

[36]  J. Kovac,et al.  AC loss in ReBCO pancake coils and stacks of them: modelling and measurement , 2011, 1109.2526.

[37]  Mark D. Ainslie,et al.  An improved FEM model for computing transport AC loss in coils made of RABiTS YBCO coated conductors for electric machines , 2011 .

[38]  Honghai Song,et al.  Quench behavior of conduction-cooled Y Ba2Cu3O7−δ coated conductor pancake coils stabilized with brass or copper , 2010 .

[39]  R. Badcock,et al.  Transport AC loss characteristics of a nine strand YBCO Roebel cable , 2010 .

[40]  F. Gömöry,et al.  Theoretical and experimental study of AC loss in high temperature superconductor single pancake coils , 2008, 0808.0061.

[41]  A. Werner,et al.  Theoretical Estimation of Electromagnetic Loss From the Movement of Superconducting Coil in the W7-X Stellarator , 2006, IEEE Transactions on Applied Superconductivity.

[42]  V. Anferov.  Combined X-Y scanning magnet for conformal proton radiation therapy. , 2005, Medical physics.