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Superconductor (SC)
SuperPower SC12050 YBCO tapes
Ferromagnet (FM)
permalloy sheet 1J85
or amorphous alloy sheet 1K107
Enhancement of the Magnetic Coupling using a
Superconductor-Ferromagnet Heterostructure from 1 to 10 kHz
Peng-Bo Zhou1, Guang-Tong Ma1, Chen Yang1, Loïc Quéval2, Gui-Ming Mei1, Kun Liu1, Hang-Yu Qian1, Kang Liu1
Purpose
1 Applied Superconductivity Lab., State Key Lab. of Traction Power, Southwest Jiaotong University, Chengdu, China
2 Group of electrical engineering - Paris (GeePs), CNRS UMR 8507, CentraleSupélec, UPSud, UPMC, Gif-sur-Yvette, France
Superconductor-Ferromagnet (SC-FM) heterostructures have been proposed for applications such as magnetic
cloaking, magnetic field concentration and long distance magnetic field transfer.
Up to now, practical SC-FM heterostructures have been demonstrated only in static and quasi-static conditions.
We investigate here their application to higher frequencies.
This is done both experimentally and numerically by comparing the performance of a simple transformer with
and without the SC-FM heterostructure from 1 to 10 kHz.
Experiment
Practical realization
cnm2017 : Colloque National Métamatériaux 2017
27-28 mars 2017, Orsay, France
Conclusion
For both FM materials, in comparison to the naked magnetic core, the efficiency of the transformer is increased by a factor two
when using a SC-FM heterostructure to enhance the magnetic coupling. This result is independent of the frequency from 1 kHz to
10 kHz. Therefore, SC-FM heterostructures may still be effective at even higher frequency. For instance, it could be used to
increase the efficiency and to reduce the electromagnetic interference of wireless power transfer systems (~20 kHz).
The agreement between measurements and simulations is good, thus validating the modeling strategy. The model enables us to
estimate the AC losses in the SC [1] and to visualize the impact of the induced supercurrent. Besides, the model could help us to
improve the SC-FM heterostructure in the future: from the plot of the magnetic field lines, we can indeed observe the magnetic
flux leakage through the SC-FM heterostructure which could be reduced by modifying the arrangement or by using wider tapes.
References
[1] P.-B. Zhou, G.-T. Ma, C. Yang, L. Quéval, K. Liu, H.-Y.
Qian, K. Liu, “Magnetic field transfer of superconductor-
ferromagnet heterostructures up to 10 kHz,” IEEE
Transactions on Applied Superconductivity, vol. 27, no. 4,
pp. 0601105, June 2017.
Equivalent circuit and efficiency
Numerical model
About
On-load case
Protocol
a) Set voltage source frequency f and load resistance RL
according to Table I
b) Cool down device to 77 K
c) Increase voltage source amplitude Vi to 1 Vrms
d) Measure primary current I1 and secondary current I2
e) Estimate the efficiency using Eq.(1).
- 2D axisymmetric H-formulation finite element model
- Superconductor modeled by an E-J power law
- Superconductor Jc(B) dependence modeled by an
anisotropic Kim-like model
- Superconductor real thickness (~1 um) included using a
mapped mesh
- Core and FM modeled as linear materials (|B|<1 T)
|B|
Jθ/Jc
10.80.60.40.20
10.50-0.5-1
Core: MnZn ferrite
Coils: copper Litz wire
LN2
Generator
+ Amplifier
Resistive
load
SC-FM
heterostructure
Superconductor (SC)
SuperPower SC12050 YBCO tapes
Ferromagnet (FM)
permalloy sheet 1J85
or amorphous alloy sheet 1K107
Setup overview
With SC-FM heterostructure
Naked magnetic core
primary secondary
core
(1)
Open-circuit case