An Improved Self-Consistent Model and Its Application to Estimate the Critical Current of REBCO Magnet

Self Cite

The double-layer metal-insulation method using the brass sheets as the double-layer insulators was proposed in this paper. It can enhance the contact resistivity while reserving greater thermal conductivity merit. The underlying mechanism of the contact resistivity enhancement is to increase the number of contact surfaces and to degrade the contact quality between the insulators. Then, we wound a single-layer brass-insulation coil and a double-layer brass-insulation coil to compare their contact resistivities and confirmed the effectiveness of the double-layer metal-insulation method. Besides, since the capacity withstanding the overcurrent is weakened with the increscent contact resistance of the metal-insulation coil, we further investigated the influence of the contact surface resistivity distribution on the coil performance under different scenarios to optimize the double-layer metal-insulation coil for receiving a superior thermal stability. Simulation results indicated that the coil possessed the dominated 2nd contact surface resistivity and minimum 1st and 3rd contact resistivity is the optimal design for the double-layer metal-insulation coil to receive the best thermal stability, irrespective of the cooling environment, contact resistivity magnitude, operating current and coil dimension. In addition, in regard to the thermal performance differences caused by the contact surface resistivity distribution, we found that the increment of contact surface resistivity and the overcurrent would enlarge the distinctions at different levels.

Section: Simulations and Analysismentioning

confidence: 99%

Performance enhancement of coated conductor magnet with double-layer metal insulation

Wang

Zhou

et al. 2023

Self Cite

“…Since the self-consistent model introduces an auxiliary variable P, this model is also called P-model [20]. Then, the application of this model is extended to racetrack magnets with Dirichlet boundary, which named improved selfconsistent model [21].…”

Section: Model Descriptionmentioning

confidence: 99%

“…Since the second generation of high temperature superconductors is multilayer REBCO coated conductors, the superconducting layer has a large width-thickness ratio of up to >1000. This makes the homogenization technique an inevitable choice [21].…”

Section: Model Descriptionmentioning

confidence: 99%

Design optimization of a stepped HTS magnet for electrodynamic suspension train

Li,

Liu,

Zhou

et al. 2023

Self Cite

High-temperature superconducting (HTS) magnets are promising candidates for transportation and power systems, such as the electrodynamic suspension (EDS) train, ultra-high field magnet and magnetic resonance imaging, because of its large current-carrying capacity and low power loss. The critical current depending on magnetic flux density is an essential factor assessing the application performance of HTS magnet. The existing HTS magnet is wound with rectangular cross-section as usual, which results in magnetic field concentration inside winding. In this paper, we proposed a novel HTS magnet structure with stepped cross-section to alleviate the magnetic field concentration, and resultantly improve the critical current. From this point, this paper is aimed to design and optimize a stepped HTS magnet with the critical current maximized. Firstly, the structure design of the stepped HTS magnet is performed with a consideration of the application scenario of EDS train. Then, the critical current of the HTS magnet is estimated with a homogenized self-consistent model. Afterwards, an HTS magnet with stepped cross-section is optimized, fabricated and finally tested. The critical current was experimentally measured to verify the simulation results, followed by the electromagnetic investigations of the stepped HTS magnet in the EDS train.

“…The T-A formulation was used in [38], to validate the developed self-consistent model, in order to estimate the critical current of a racetrack REBCO magnet. The evaluated relative error between the models was 0.48% for the whole coil and an identical magnetic field distribution.…”

Section: High Field Magnetsmentioning

confidence: 99%

The T-A formulation: an efficient approach to model the macroscopic electromagnetic behaviour of HTS coated conductor applications

Huber

Song

Zhang

et al. 2022

In recent years, the T-A formulation has emerged as an efficient approach for modelling the electromagnetic behaviour of high-temperature superconductor (HTS) tapes in the form of coated conductors (CCs). HTS CCs are characterized by an extremely large width-to-thickness ratio of the superconducting layer, normally up to 1000~6000, which in general leads to a very large number of degrees of freedom. The T-A formulation considers the superconducting layer as infinitely thin. The magnetic vector potential A is used to calculate the magnetic field distribution in all simulated domains. The current vector potential T is used to calculate the current density in the superconducting layer, which is a material simulated with a highly nonlinear power-law resistivity. This article presents a review of the T-A formulation. First, the governing equations are described in detail for different cases (2D and 3D, cartesian and cylindrical coordinates). Then, the literature on the implementation of T-A formulation for simulating applications ranging from simple tape assemblies to high field magnets is reviewed. Advantages and disadvantages of this approach are also discussed.