Dynamic resistance and total loss in a three-tape REBCO stack carrying DC currents in perpendicular AC magnetic fields at 77 K

2022 ◽  
Author(s):  
Yueming Sun ◽  
Jin Fang ◽  
Gennady Sidorov ◽  
Rodney Alan Badcock ◽  
Nicholas J Long ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Operating Conditions ◽  
Total Loss ◽  
Ac Loss ◽  
Dynamic Resistance ◽  
Magnetization Loss ◽  
Loss Component ◽  
Dynamic Loss ◽  
Dc Current

Abstract In many high-temperature superconducting (HTS) applications, HTS coated conductors carry a DC current under an external AC magnetic field. In such operating conditions, dynamic resistance will occur when the traversing magnetic flux across the HTS conductors. Consequently, AC loss within the superconductors is composed of the dynamic loss component arising from dynamic resistance and the magnetization loss component due to the AC external magnetic field. In this work, the dynamic resistance and the total loss in a three-tape HTS coated conductor stack were measured at 77 K under perpendicular AC magnetic fields up to 80 mT and DC currents (Idc) up to the critical current (Ic). The stack was assembled from three serial-connected 4 mm wide Superpower wires. The measured dynamic resistance results for the stack were well supported by the results from 2D H-formulation finite element modelling (FEM) and broadly agree with the analytical values for stacks. The FEM analysis shows asymmetric transport DC current profiles in the central region of the superconductor. We attribute the result to the superposition of DC currents and the induced subcritical currents which explains why the measured magnetization loss values increase with DC current levels at low magnetic field. The onset of dynamic loss for the stack for low i (Idc/ Ic) values is much slower when compared to that of the single tape and hence the contribution of the dynamic loss component to the total loss in the stack is much smaller than that of the single tape. Dynamic loss in the stack becomes comparable to the magnetization loss at i = 0.5 and becomes greater than the magnetization loss at i = 0.7. Both magnetization loss and dynamic loss in the stack are smaller than those of the single tape due to shielding effects.

Current Induced Spin Injection in Si-MOSFET

2012 ◽  
Vol 190 ◽  
pp. 129-132
Author(s):  
I. Shlimak ◽  
A. Butenko ◽  
D.I. Golosov ◽  
K.J. Friedland ◽  
S.V. Kravchenko
Keyword(s):  
Magnetic Fields ◽  
Spin Injection ◽  
Dynamic Resistance ◽  
Experimental Scheme ◽  
Ac Current ◽  
Sample Resistance ◽  
Pass Through ◽  
Lock In ◽  
Dc Current ◽  
Parallel Magnetic Fields

Longitudinal resistivity in strong parallel magnetic fields up to B = 14 Tesla was measured in Si-MOSFET with a narrow slot (90nm) in the upper metallic gate that allows to apply different gate voltage across the slot and, therefore, to control the electron density n1 and n2 in two parts of the sample independently. The experimental scheme allows us to pass through the source-drain channel relatively large DC current (IDC), while the dynamic resistance was measured using a standard lock-in technique with small AC current. It was shown that the sample resistance is asymmetric with respect to the direction of DC current. The asymmetry increases with increase of magnetic field, DC current, and difference between n1 and n2. Results are interpreted in terms of a current-induced spin accumulation or depletion near the slot, as described by a spin drift-diffusion equation. The effect on the sample resistance is due to the positive magnetoresistance of Si-MOSFETs in parallel magnetic fields.

scholarly journals The dynamic resistance of YBCO coated conductor wire: Effect of DC current magnitude and applied field orientation

2021 ◽  
Author(s):  
Zhenan Jiang ◽  
W Zhou ◽  
Q Li ◽  
M Yao ◽  
J Fang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Applied Field ◽  
Threshold Field ◽  
Dynamic Resistance ◽  
Coated Conductor ◽  
Field Orientation ◽  
Ac Magnetic Field ◽  
Ybco Coated Conductor ◽  
Wide Range ◽  
Dc Current

Dynamic resistance, which occurs when a HTS coated conductor carries a DC current under an AC magnetic field, can have critical implications for the design of HTS machines. Here, we report measurements of dynamic resistance in a commercially available SuperPower 4 mm-wide YBCO coated conductor, carrying a DC current under an applied AC magnetic field of arbitrary orientation. The reduced DC current, I t/I c0, ranged from 0.01 to 0.9, where I t is the DC current level and I c0 is the self-field critical current of the conductor. The field angle (the angle between the magnetic field and the normal vector of the conductor wide-face) was varied between 0° and 90° at intervals of 10°. We show that the effective width of the conductor under study is ∼12% less than the physical wire width, and we attribute this difference to edge damage of the wire during or after manufacture. We then examine the measured dynamic resistance of this wire under perpendicular applied fields at very low DC current levels. In this regime we find that the threshold field, B th, of the conductor is well described by the nonlinear equation of Mikitik and Brandt. However, this model consistently underestimates the threshold field at higher current levels. As such, the dynamic resistance in a coated conductor under perpendicular magnetic fields is best described using two different equations for each of the low and high DC current regimes, respectively. At low DC currents where I t/I c0 ≤ 0.1, the nonlinear relationship of Mikitik and Brandt provides the closest agreement with experimental data. However, in the higher current regime where I t/I c0 ≥ 0.2, closer agreement is obtained using a simple linear expression which assumes a current-independent penetration field. We further show that for the conductor studied here, the measured dynamic resistance at different field angles is dominated by the perpendicular magnetic field component, with negligible contribution from the parallel component. Our findings now enable the dynamic resistance of a single conductor to be analytically determined for a very wide range of DC currents and at all applied field angles. This is the Accepted Manuscript version of an article accepted for publication in 'Superconductor Science and Technology'. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6668/aaa49e.

scholarly journals Numerical modelling of dynamic resistance in high-temperature superconducting coated-conductor wires

2021 ◽  
Author(s):  
MD Ainslie ◽  
Christopher Bumby ◽  
Zhenan Jiang ◽  
R Toyomoto ◽  
N Amemiya
Keyword(s):  
Magnetic Fields ◽  
Angular Dependence ◽  
Flow Resistance ◽  
Transport Current ◽  
Ac Loss ◽  
Dynamic Resistance ◽  
Coated Conductor ◽  
Superconducting Properties ◽  
Flux Flow ◽  
The Wire

The use of superconducting wire within AC power systems is complicated by the dissipative interactions that occur when a superconductor is exposed to an alternating current and/or magnetic field, giving rise to a superconducting AC loss caused by the motion of vortices within the superconducting material. When a superconductor is exposed to an alternating field whilst carrying a constant DC transport current, a DC electrical resistance can be observed, commonly referred to as ‘dynamic resistance.’ Dynamic resistance is relevant to many potential hightemperature superconducting (HTS) applications and has been identified as critical to understanding the operating mechanism of HTS flux pump devices. In this paper, a 2D numerical model based on the finite-element method and implementing the H-formulation is used to calculate the dynamic resistance and total AC loss in a coated-conductor HTS wire carrying an arbitrary DC transport current and exposed to background AC magnetic fields up to 100 mT. The measured angular dependence of the superconducting properties of the wire are used as input data, and the model is validated using experimental data for magnetic fields perpendicular to the plane of the wire, as well as at angles of 30° and 60° to this axis. The model is used to obtain insights into the characteristics of such dynamic resistance, including its relationship with the applied current and field, the wire’s superconducting properties, the threshold field above which dynamic resistance is generated and the flux-flow resistance that arises when the total driven transport current exceeds the field-dependent critical current, Ic(B), of the wire. It is shown that the dynamic resistance can be mostly determined by the perpendicular field component with subtle differences determined by the angular dependence of the superconducting properties of the wire. The dynamic resistance in parallel fields is essentially negligible until Jc is exceeded and flux-flow resistance occurs.

scholarly journals Dynamic resistance measurements in a GdBCO-coated conductor

2021 ◽  
Author(s):  
Zhenan Jiang ◽  
R Toyomoto ◽  
N Amemiya ◽  
Christopher Bumby ◽  
Rodney Badcock ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Dynamic Resistance ◽  
Normal Vector ◽  
Coated Conductor ◽  
Personal Use ◽  
Perpendicular Component ◽  
Experimental Values ◽  
Dc Current ◽  
Heat Loads ◽  
The Magnetic Field

Dynamic resistance is a phenomenon which occurs when a superconducting wire carries dc transport current whilst experiencing an alternating magnetic field. This situation occurs in a range of HTS machinery applications, where dynamic resistance can lead to large parasitic heat loads and potential quench events. Here, we present dynamic resistance measurements of a 5-mm-wide Fujikura coated conductor wire at 77 K. We report experimental values obtain through varying the field angle (the angle between magnetic field and normal vector of the conductor wide-face), the dc current levels, and the magnetic field amplitude, and frequency. We show that the dynamic resistance in perpendicular magnetic field can be predicted by using a simple analytical equation. We also show that across the range of field angles measured here the dynamic resistance is dominated by the perpendicular component of the applied magnetic field. © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

scholarly journals Dynamic Resistance Measurement of a Four-Tape YBCO Stack in a Perpendicular Magnetic Field

2021 ◽  
Author(s):  
Zhenan Jiang ◽  
W Zhou ◽  
Christopher Bumby ◽  
M Staines ◽  
Q Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Role ◽  
Coated Conductors ◽  
Threshold Field ◽  
Dynamic Resistance ◽  
Perpendicular Magnetic Field ◽  
Personal Use ◽  
Dc Current ◽  
The Magnetic Field ◽  
Circulating Currents

Dynamic resistance occurs when HTS (high-temperature superconductor) coated conductors carry dc current under ac magnetic field. This dissipative effect can play a critical role in many HTS applications. Here, we report on dynamic resistance measurements of a four-tape YBCO stack comprising 4-mm-wide coated conductors, which experience an applied ac perpendicular magnetic field with an amplitude of up to 100 mT. Each tape within the stack carries the same dc current. The magnetic field amplitude, the frequency of the magnetic field, and the dc current magnitude are varied to investigate the influence of these parameters on the dynamic resistance. We find that the threshold field of the stack is significantly larger than that of a single tape when dc current is small, which we attribute to coherent shielding effects from circulating currents present in each wire in the stack. © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

scholarly journals Numerical modelling of dynamic resistance in high-temperature superconducting coated-conductor wires

2021 ◽  
Author(s):  
MD Ainslie ◽  
Christopher Bumby ◽  
Zhenan Jiang ◽  
R Toyomoto ◽  
N Amemiya
Keyword(s):  
Magnetic Fields ◽  
Angular Dependence ◽  
Flow Resistance ◽  
Transport Current ◽  
Ac Loss ◽  
Dynamic Resistance ◽  
Coated Conductor ◽  
Superconducting Properties ◽  
Flux Flow ◽  
The Wire

The use of superconducting wire within AC power systems is complicated by the dissipative interactions that occur when a superconductor is exposed to an alternating current and/or magnetic field, giving rise to a superconducting AC loss caused by the motion of vortices within the superconducting material. When a superconductor is exposed to an alternating field whilst carrying a constant DC transport current, a DC electrical resistance can be observed, commonly referred to as ‘dynamic resistance.’ Dynamic resistance is relevant to many potential hightemperature superconducting (HTS) applications and has been identified as critical to understanding the operating mechanism of HTS flux pump devices. In this paper, a 2D numerical model based on the finite-element method and implementing the H-formulation is used to calculate the dynamic resistance and total AC loss in a coated-conductor HTS wire carrying an arbitrary DC transport current and exposed to background AC magnetic fields up to 100 mT. The measured angular dependence of the superconducting properties of the wire are used as input data, and the model is validated using experimental data for magnetic fields perpendicular to the plane of the wire, as well as at angles of 30° and 60° to this axis. The model is used to obtain insights into the characteristics of such dynamic resistance, including its relationship with the applied current and field, the wire’s superconducting properties, the threshold field above which dynamic resistance is generated and the flux-flow resistance that arises when the total driven transport current exceeds the field-dependent critical current, Ic(B), of the wire. It is shown that the dynamic resistance can be mostly determined by the perpendicular field component with subtle differences determined by the angular dependence of the superconducting properties of the wire. The dynamic resistance in parallel fields is essentially negligible until Jc is exceeded and flux-flow resistance occurs.

scholarly journals Dynamic resistance measurements in a GdBCO-coated conductor

2021 ◽  
Author(s):  
Zhenan Jiang ◽  
R Toyomoto ◽  
N Amemiya ◽  
Christopher Bumby ◽  
Rodney Badcock ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Dynamic Resistance ◽  
Normal Vector ◽  
Coated Conductor ◽  
Personal Use ◽  
Perpendicular Component ◽  
Experimental Values ◽  
Dc Current ◽  
Heat Loads ◽  
The Magnetic Field

Dynamic resistance is a phenomenon which occurs when a superconducting wire carries dc transport current whilst experiencing an alternating magnetic field. This situation occurs in a range of HTS machinery applications, where dynamic resistance can lead to large parasitic heat loads and potential quench events. Here, we present dynamic resistance measurements of a 5-mm-wide Fujikura coated conductor wire at 77 K. We report experimental values obtain through varying the field angle (the angle between magnetic field and normal vector of the conductor wide-face), the dc current levels, and the magnetic field amplitude, and frequency. We show that the dynamic resistance in perpendicular magnetic field can be predicted by using a simple analytical equation. We also show that across the range of field angles measured here the dynamic resistance is dominated by the perpendicular component of the applied magnetic field. © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

scholarly journals Dynamic Resistance Measurement in a Four-Tape YBCO Stack with Various Applied Field Orientation

2021 ◽  
Author(s):  
Y Liu ◽  
Zhenan Jiang ◽  
Q Li ◽  
Christopher Bumby ◽  
Rodney Badcock ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Buffer Layers ◽  
Analytical Models ◽  
Dynamic Resistance ◽  
Normal Vector ◽  
Field Frequency ◽  
Field Orientation ◽  
Personal Use ◽  
Dc Current ◽  
The Magnetic Field

The dynamic resistance which occurs when a superconductor carrying DC current is exposed to alternating magnetic field plays an important role in HTS applications such as flux pumps and rotating machines. We report experimental results on dynamic resistance in a four-tape coated conductor stack when exposed to AC magnetic fields with different magnetic field angles (the angles between the magnetic field and normal vector component of the tape surface, θ) at 77 K. The conductors for the stack are 4-mm-wide SuperPower SC4050 wires. The field angle was varied from 0° to 120° at a resolution of 15° to study the field angle dependence of dynamic resistance on field angle as well as wire Ic (B, θ). We also varied the field frequency, the magnetic field amplitude, and the DC current level to study the dependence of dynamic resistance on these parameters. Finally, we compared the measured dynamic resistance results at perpendicular magnetic field with the analytical models for single wires. Our results show that the dynamic resistance of the stack was mainly, but not solely, determined by the perpendicular magnetic component. Ic (B, θ) influences dynamic resistance in the stack due to tilting of the crystal lattice of the superconductor layer with regard to buffer layers. © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

scholarly journals Dynamic Resistance Measurement in a Four-Tape YBCO Stack with Various Applied Field Orientation

2021 ◽  
Author(s):  
Y Liu ◽  
Zhenan Jiang ◽  
Q Li ◽  
Christopher Bumby ◽  
Rodney Badcock ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Buffer Layers ◽  
Analytical Models ◽  
Dynamic Resistance ◽  
Normal Vector ◽  
Field Frequency ◽  
Field Orientation ◽  
Personal Use ◽  
Dc Current ◽  
The Magnetic Field

The dynamic resistance which occurs when a superconductor carrying DC current is exposed to alternating magnetic field plays an important role in HTS applications such as flux pumps and rotating machines. We report experimental results on dynamic resistance in a four-tape coated conductor stack when exposed to AC magnetic fields with different magnetic field angles (the angles between the magnetic field and normal vector component of the tape surface, θ) at 77 K. The conductors for the stack are 4-mm-wide SuperPower SC4050 wires. The field angle was varied from 0° to 120° at a resolution of 15° to study the field angle dependence of dynamic resistance on field angle as well as wire Ic (B, θ). We also varied the field frequency, the magnetic field amplitude, and the DC current level to study the dependence of dynamic resistance on these parameters. Finally, we compared the measured dynamic resistance results at perpendicular magnetic field with the analytical models for single wires. Our results show that the dynamic resistance of the stack was mainly, but not solely, determined by the perpendicular magnetic component. Ic (B, θ) influences dynamic resistance in the stack due to tilting of the crystal lattice of the superconductor layer with regard to buffer layers. © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

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