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By the introduction of a generalized magnetic vector potential, which contains the contributions of both the magnetic and electric parts, and the use of the Ampere's law within the quasistatic approximation as the state equation, the partial differential equations for governing the electromagnetic properties of superconductors as well as the surrounding coolant were established and numerically discretized by resorting to the finite-element technique and finite-difference scheme, respectively, in the spatial and temporal domain. In conjunction with an analytic method to calculate the magnetic field generated by permanent magnet, we compiled a numerical tool for performing an intricate study of the mutual effect among the superconducting constituents in a superconducting levitation system with translational symmetry. Taking a superconducting unit with three constituents inside as a practice, we simulated the electromagnetic responses of this unit while moving in the nonuniform magnetic field generated by permanent magnet guideway and, identified the influences of the mutual effect on the levitation force as well as on the distributions of the magnetic flux density, the supercurrent density, and the levitation force density by comparing to an envisaged reference, one constituent was simulated with all the rest absent to remove the mutual effect. The insights attained by the present study, mostly being inaccessible from the experiments, are aimed to provide useful implications for the design of a superconducting levitation system for the transit and analogous purposes, which usually employ multiple superconductors to achieve the desired capability. [ABSTRACT FROM AUTHOR]

Multiseeded YBaCuO bulk crystallized by melt growth process is usually employed as the levitated magnet in high-temperature superconducting (HTS) maglev system. However, to the state of art, the intergrain supercurrent between different domains in the multiseeded bulk superconductor is much harder to simulate than the intragrain supercurrent in the single-seeded bulk, hindering the numerical study of multiseeded bulks. In this paper, we first discussed how to simulate the electromagnetic response of multiseeded bulk superconductor levitated above permanent magnetic guideway (PMG) through treating the multiseeded bulk as magnetically coupling but electric uncoupling domains, discriminating from assuming it as a single-seeded bulk superconductor. This model was validated through experiments of a three-seeded bulk levitated at different positions above a Halbach-derived PMG, comparing with a single-seeded bulk with the same geometrical dimensions. To realize a heavy-load HTS maglev system that can carry over a ton per meter length of levitation constituent, we introduced the feasible paths to increase the load, increasing the volumes of superconductors and PMs. We also optimized the selective configurations of the HTS maglev system by the genetic algorithm to reduce the total cost. The final summarized rules for designing the heavy-load HTS maglev system applied multiseeded bulk superconductors and Halbach-derived PMGs are deemed important to industrial-level application. [ABSTRACT FROM AUTHOR]

As diamagnetic materials, superconductors confine magnetic fields efficiently. Based on this property, we designed and fabricated a novel contactless power transfer (CPT) coupler consisting of a ferrite core wrapped with superconductor layers, which results in an obvious enhancement of the coupling coefficient. We analyzed the underlying causes of coupling enhancement with a magnetic circuit model. Additionally, we used finite-element simulations to investigate the performance of the structure as a function of applied frequency. The results predict that the coupler would be efficient up to 50 kHz. Thus, the modified coupler should be practical for CPT systems. [ABSTRACT FROM PUBLISHER]

In this paper, the 3-D model proposed in Part I of this study is verified in detail on the basis of a levitation/suspension system composed of a rectangular single-domain Y-Ba-Cu-O and a cylindrical Nd-Fe-B magnet or a permanent magnet guideway (PMG) assembled by the Nd-Fe-B magnets. The magnetic forces along the vertical direction perpendicular or the transverse direction parallel to the surface of the PMG(or magnet) were calculated and compared well with the measured data under vertical and transverse displacements. The computed results of the induced current distribution within the Y-Ba-Cu-O domain, as well as the magnetic field profiles in the Y-Ba-Cu-O and its vicinal region, were also presented and discussed. [ABSTRACT FROM AUTHOR]

A magnetic levitation technique with high-Tc superconductor (HTS) has received significant interest for a wide range of applications after its discovery due to its unique inherent stability, which gives a fundamental significance to evaluate the HTS magnetic levitation in both experiment and calculation. To numerically investigate the HTS magnetic levitation, a 3-D model describing the electromagnetic property of the HTS, including its anisotropic behavior, was established by incorporating the current vector potential and Helmholtz's theorem. In addition to the commonly considered nonlinear E--J characteristic in the reported calculation, we introduce an elliptical model to formulate the angular dependence of the critical current density Jc resulting from the anisotropic behavior of the HTS. To numerically resolve the governing equations of the 3-D model, Galerkin's finite-element method and the Crank--Nicolson-θ method were employed to discretize the governing equations in space and time domains, respectively. The obtained algebraic equations were firstly linearized by the Newton--Raphson method, and then an extended format of the incomplete Cholesky-conjugate gradient method was applied to solve the linear algebraic equations. The 3-D model was implemented by a self-written numerical program based on a VC++ platform to calculate the magnetic force of a bulk HTS exposed to applied field generated by a permanent magnet guideway (PMG) assembled by the Nd-F-e-B magnets. In this paper, we present the numerical results of the levitation force of a moving bulk HTS above the PMG with different mesh densities and number of time steps. This presents a preliminary validation of the 3-D model proposed in this paper. [ABSTRACT FROM AUTHOR]

A three-dimensional analytical method is proposed to model the permanent magnet guideway (PMG) involved in the high-temperature superconducting (HTS) maglev vehicle system, and with this analytical method, the non-uniformity of magnetic field along the longitudinal direction of the PMG due to the existent gap between the adjacent permanent magnet (PM) can be taken into account in the simulation of the HTS maglev vehicle system. The analytical expressions for two rectangular PM with different magnetization directions are deduced from the Biot–Savart’s law. The 3D modeling of the PMG is validated from the four aspects, i.e., the comparison of the measurement and calculation value of the magnetic field; the magnetic field contour of the PMG; the comparison of the 3D method results with the 2D method; and the comparison of the results from the present 3D analytical model and previous finite element software. Currently, using the 3D analytical model, we have proposed a 3D method to numerically investigate the HTS magnetic levitation/suspension system with bulk high-temperature superconductor (HTSC). [ABSTRACT FROM AUTHOR]

We explore the possibility of improving the magnetic coupling between two distant coils by using a flux transformer. A flux transformer is a short-circuited coil operating in constant flux mode. It could be an alternative for applications where it would not be suitable to use a magnetic core. From the circuit model of an air-cored inductive power transfer (IPT) system, we show that the flux transformer allows for magnetic coupling of systems separated by a large distance, even at low frequencies. A flux transformer can be practically obtained with a joint-free superconducting (SC) coil. We demonstrate here how this can be done using a laser-cut high temperature SC ReBCO coated conductor. Experimental results confirm the prediction of the circuit model and the corresponding finite element (FE) model. The flux transformer opens the door to new kinds of IPT systems. [ABSTRACT FROM AUTHOR]