AC loss calculation in REBCO coils or stacks by solving the equation of motion for current using an integration approach

Lai, Lingfeng; Gu, Chen

doi:10.1088/1361-6668/abc567

Cited by 19 publications

(28 citation statements)

References 21 publications

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“…R j,k represents the k-th radial resistance. To further investigate the evolution of current distributions, understand the more quantitative characteristics during the transition to the magnetic-field saturation phase, and clarify the potential risks of NI coils during overcurrent excitation, this study adopted an equivalent circuit grid model [15][16][17] coupled with a magnetic field the E-J power law of superconductors, calculated by the method mentioned in [20], to realize a real-time circuit-field simulation. In addition, a double pancake NI test coil was wound and charged with exquisite excitation procedures to validate the model.…”

Section: Model Description 21 Double-pancake Ecg Modelmentioning

confidence: 99%

“…To calculate the field-dependent critical current effectively, a two-dimensional axisymmetric model mentioned in [20] was used as Equation (6).…”

Section: Coupling Of Magnetic Fields and The Dp Ecg Modelmentioning

confidence: 99%

“…The magnetic vector potentials A(r, φ, z) can be calculated by integrating the current density multiplied by an integral kernel [20]. Numerically, only two linear transformations are needed to obtain the parallel component B par and perpendicular component B per of the magnetic field by multiplying the current density with two pre-calculated constant matrices.…”

Section: Coupling Of Magnetic Fields and The Dp Ecg Modelmentioning

confidence: 99%

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Magnetic Field Saturation of Non-Insulation High-Temperature Superconducting Coils during Overcurrent

Gao

Jin

2021

Electronics

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Non-insulation high-temperature superconducting coils provide a much lower risk of burnout in fault/abnormal conditions, such as hot-spot quench and overcurrent. This study employs an equivalent circuit grid model, coupled with magnetic field calculation and the E–J power law of superconductors, to deeply and systematically investigate the overcurrent charging process in a double-pancake non-insulation coil. An evident saturation of the magnetic field in the axial direction of the coil was observed and verified by experiments. Experimentally, the entire process, including the behavior of the magnetic field, was consistent with the numerical results. Based on the verified model, two main points were addressed: (1) Transient current distribution inside the coil during overcurrent charging was studied. Potential quenching risks were found to be at the innermost and outermost turn near the electrodes, as well as the pancake-to-pancake connection part. (2) Magnetic field saturation, which is a unique phenomenon in non-insulation superconducting coils during overcurrent charging, was studied in detail and first quantitatively defined by a new concept “converged load factor”. Its relationship with turn-to-turn resistivity was revealed.

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Section: Model Description 21 Double-pancake Ecg Modelmentioning

confidence: 99%

“…To calculate the field-dependent critical current effectively, a two-dimensional axisymmetric model mentioned in [20] was used as Equation (6).…”

Section: Coupling Of Magnetic Fields and The Dp Ecg Modelmentioning

confidence: 99%

Section: Coupling Of Magnetic Fields and The Dp Ecg Modelmentioning

confidence: 99%

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Magnetic Field Saturation of Non-Insulation High-Temperature Superconducting Coils during Overcurrent

Gao

Jin

2021

Electronics

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“…The thin sheet approximation is adopted to simplify the geometry and enables effective simulation of HTS tapes because of the high aspect ratio of the superconducting layer. Additionally, the FFT-based method [37][38][39], the J formulation [40,41], and the minimum electromagnetic entropy production method [42][43][44] are also developed to calculate the electromagnetic response of HTS. Discussions on different numerical modeling techniques for superconductors can be found in [45,46].…”

Section: Introductionmentioning

confidence: 99%

Numerical calculations of high temperature superconductors with the J-A formulation

Wang,

Yong,

Zhou

2023

Supercond. Sci. Technol.

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One of the main challenges in superconductivity modeling stems from the strong nonlinearity of the E-J power law relationship. To overcome this difficulty, various numerical models have been developed by the superconductivity community, such as the H formulation and the T-A formulation. These models are implemented based on different state variables in Maxwell’s equations and have the advantage of efficiency and versatility. In this study, a finite element model based on the J-A formulation is further developed to enhance its accuracy and versatility. The discontinuous Lagrange shape function is employed in the J formulation to stabilize the numerical results. Meanwhile, the Lagrange multiplier method is applied to impose the transport current on the superconductors. In terms of applications, the J-A formulation can efficiently simulate the electromagnetic responses not only of superconducting films but also of superconducting bulks. Moreover, homogeneous and multi-scale strategies are introduced to simplify the model and reduce the computation cost, allowing efficient simulation of large-scale HTS systems. Finally, the three-dimensional (3D) J-A formulation is proposed to incorporate the 3D structure of HTS systems, examples including the CORC cables as well as the racetrack coils. These results reveal that the J-A formulation is an efficient and versatile numerical method for calculating the electromagnetic behavior of high temperature superconductors.

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“…The A-V formulation, T-A formulation, T-Ω formulation and multi-scale model are also effective for HTS magnets to electromagnetic calculation [16][17][18][19][20]. An integral method for the calculation of the flux motion in an HTS coil subjected to a self-field and an applied field is proposed [21]. 'Dimensionality reduction and inversion' is approached to analyze AC loss of toroidal magnets [22].…”

Section: Introductionmentioning

confidence: 99%

An electromagnetic-thermal-mechanical analysis model for high temperature superconducting magnets

Yang¹,

Ren²,

Xu³

et al. 2023

Phys. Scr.

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High temperature superconducting magnet is the core component of superconducting power device, and its stability is the key factor that restricts the safe operation of superconducting power devices. In order to accurately and effectively evaluate the stability of superconducting magnets during operation, an electromagnetic-thermal-mechanical numerical simulation method for high temperature superconducting magnets is studied in this paper. Based on the model, the 150kJ SMES magnet as case is studied, the magnetic field and current density distribution are solved during the operation of the 150 kJ magnet, and its temperature rise, AC loss and stress analysis of the magnet are achieved. In addition, this work further analyses the critical current declination degree of superconducting tapes in the 150kJ HTS magnet under multi-field coupling, the dangerous region in operation is obtained and suggestions are put forward to avoid quench. The electromagnetic-thermal-mechanical model may provide an appropriate stability assessment with rapid and real-time calculations for HTS magnets.

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AC loss calculation in REBCO coils or stacks by solving the equation of motion for current using an integration approach

Cited by 19 publications

References 21 publications

Magnetic Field Saturation of Non-Insulation High-Temperature Superconducting Coils during Overcurrent

Magnetic Field Saturation of Non-Insulation High-Temperature Superconducting Coils during Overcurrent

Numerical calculations of high temperature superconductors with the J-A formulation

An electromagnetic-thermal-mechanical analysis model for high temperature superconducting magnets

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