Dynamic resistance and dynamic loss in a ReBCO superconductor

Zhang, Hongye; Shen, Boyang; Chen, Xiao Yuan; Jiang, Zhenan

doi:10.1088/1361-6668/ac95d5

Cited by 18 publications

(13 citation statements)

References 112 publications

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“…Within the regime of critical state model, in sections [x 1 , x 2 ] and [x 3 , x 4 ], the current density should not be greater than J c , otherwise flux will move towards the undesired dynamic resistance direction and cause [47][48][49], which gives…”

Section: Operational Principlesmentioning

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: Operational Principlesmentioning

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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“…HTS coated conductors are exposed to an AC magnetic field while carrying a DC current. Once the applied magnetic field exceeds the threshold magnetic field, a non-zero DC resistance occurs in the superconductors and this effect is known as dynamic resistance [9], [10], [11], [12]. Two types of losses are generated under this condition: one is magnetization loss due to shielding currents caused by the external magnetic field; the other is dynamic loss from dynamic resistance due to the interaction of the DC current and AC magnetic field.…”

Section: Introductionmentioning

confidence: 99%

“…To date, many previous works on dynamic resistance and total loss have mainly focused on single HTS coated conductor tapes [12], [13], [14], [15], [16], [17] or stacks [3], [18], [19], [20], [21], [22], [23]. In terms of the operating conditions, the dependence of dynamic resistance and total loss of single REBCO coated conductors on magnetic field/DC current/temperature/frequency have been investigated through experiments [13], [14], [15].…”

Section: Introductionmentioning

confidence: 99%

Simulation of Dynamic Resistance and Total Loss of HTS CORC Cables

et al. 2023

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In some high temperature superconducting (HTS) applications, HTS coated conductors carry DC current under external AC magnetic fields. Dynamic resistance occurs when the amplitude of the magnetic field is greater than the threshold magnetic field of the coated conductors. The resulting AC loss, termed as total loss, consists of dynamic loss due to dynamic resistance and magnetization loss due to the shielding currents caused by the AC magnetic field. Conductor on round core (CORC) cables wound with HTS coated conductors have attracted broad attention due to their large current-carrying capability and mechanical flexibility for coil applications. However, there has been no report on dynamic resistance and total loss in CORC cables. In this work, we present 3D FEM simulation results on the dynamic resistance and total loss of a spiral tape and three CORC cables, based on the T −A formulation. The number of layers of the CORC cables, the amplitude of the AC magnetic field and transport DC current levels have been varied to study the impact of those parameters on dynamic resistance and total loss of the three CORC cables. The simulation results show that magnetization loss without current in a spiral tape can be analytically estimated by Brandt and Indenbom's theoretical equation for a superconducting strip under perpendicular AC magnetic field with a geometric coefficient 2/π. Furthermore, dynamic resistance of the spiral tape and each tape in a single-layer cable can be predicted by the analytical equation for a strip carrying DC current under perpendicular AC magnetic field, also taking into account the geometric coefficient 2/π. The simulation results also show that the difference of total loss values in the three CORC cables depends on the shielding effect: the more layers of CORC cables, the lower each loss component. The two-layer Cable with each tape in the outer layer sitting on top of the tape in the inner layer has the lowest loss and the highest threshold magnetic field.

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“…However, NI magnets can be operated under nonnegligible AC fields, such as in synchronous machines of electric aircraft [4], wind turbines [5], maglev trains [6], and electric ships [7]. Under such conditions, dynamic resistance is generated in HTS tapes [8,9]. The dynamic resistance generation is commonly understood by the magnetic field profiles inside the superconductor [9][10][11][12][13] as shown in figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…Under such conditions, dynamic resistance is generated in HTS tapes [8,9]. The dynamic resistance generation is commonly understood by the magnetic field profiles inside the superconductor [9][10][11][12][13] as shown in figure 1. The flux enters the superconductor during the AC field rising (i.e.…”

Section: Introductionmentioning

confidence: 99%

Time-variant magnetic field, voltage, and loss of no-insulation (NI) HTS magnet induced by dynamic resistance generation from external AC fields

Zhong

et al. 2023

Supercond. Sci. Technol.

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High-temperature superconducting (HTS) coils serving as DC magnets can be operated under non-negligible AC fields, like in synchronous machines of maglev trains and wind turbines. In these conditions, dynamic resistance generates in HTS tapes, causing redistribution/bypassing of the transport current inside the no-insulation (NI) coil and its unique operational features. This issue was studied by experiments on an NI coil with DC current supply put into external AC fields. Due to the current redistribution induced by dynamic resistance, the central magnetic field and voltage of the NI magnet initially undergo various transient processes, and eventually exhibit a stable central magnetic field reduction and a DC voltage. These time evolutions have implications for a time-varying torque and loss of an HTS machine. These time evolutions are strongly affected by the contact resistivity distribution, and whether it is the first time of the NI magnet being exposed to the AC field, showing several qualitatively different waveforms (e.g., some are even non-monotonic with time). The magnitudes of the stable central field reductions, and their observed linear correlation with the DC voltages are found to be decided by the local contact resistivity of the innermost and outermost several turns. It is also noted that the non-insulated turn-to-turn contact help lessening the loss induced by the dynamic resistance. A numerical model is established to analyse/explain those experimental results by observing the microscopic current distribution. Two risks of quench are noticed: (i) azimuthal current of the middle part turns increases as the AC field is applied; (ii) a concentration of radial current is observed near the terminals of the NI coil.

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Dynamic resistance and dynamic loss in a ReBCO superconductor

Cited by 18 publications

References 112 publications

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

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

Simulation of Dynamic Resistance and Total Loss of HTS CORC Cables

Time-variant magnetic field, voltage, and loss of no-insulation (NI) HTS magnet induced by dynamic resistance generation from external AC fields

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