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The purpose of this study is to investigate a novel rotor design model to improve the technical performance of a superconducting synchronous generator.

Superconducting synchronous generators with a modular rotating cryostat for a single coil of the superconducting winding instead of an old-style single cryostat in which all rotor components are cold are briefly discussed. Subsequently, a new method of cryostat arrangement in the magnetic system of a rotor is considered. Different options were compared for the cryostat placement. The advantages of the novel rotor design model are noted.

In the novel rotor design model, the leakage coefficient of the excitation winding decreases, and the air gap magnetic flux increases, which will save on a superconductor material.

For the purposes of this investigation, a finite element study of flux distribution in the cross section of a superconducting synchronous generator with a 10 MW rating at 10 rpm was conducted, and the magnetic fluxes and air gap flux densities were obtained for different modes. For direct-drive superconducting synchronous generators with distributed winding and different pole numbers, the calculations of magnetic fluxes were carried out by calculating the magnetic conductivities.

A new method of the cryostat arrangement in the magnetic system of a rotor has been classified as an invention and was protected by a patent. This paper is directly applicable to the field of superconducting synchronous generators.

To investigate the feasibility of a novel scheme of high‐efficiency induction heater for nonmagnetic metal billets which use superconducting coils.

The idea is to force the billet to rotate in a static magnetic field produced by a DC superconducting magnet. Since a static superconducting magnet has no losses, the efficiency of the system is the efficiency of the motor used. In order to evaluate the temperature distribution arising from the field profile produced by a given SC coil configuration, a numerical model, based on an equivalent electric network with temperature‐dependent parameters, is developed.

A substantial independence of the shape of the temperature profile on the angular velocity and the value of the uniform magnetic field applied, is observed. A strong temperature gradient is observed in the radial direction in the proximity of the penetration front and in the axial direction at the top and bottom surface of the billet. Small temperature gradient was observed in the central part of the billet.

The reported temperature profile is inadequate for an actual extrusion process which is desired to happen at a constant temperature. The appropriate profile along the billet length can be achieved by a suitable axial shaping of the magnetic field, through the optimization of the coil layout, whereas the undesired radial gradient can be reduced by interspacing the rotation with temperature smoothing intervals.

The investigation of the profile of applied magnetic field and the heating procedure which allow to achieve the distribution of temperature suitable for the extrusion process can be carried out by using the present model.

A high‐efficiency induction heater for nonmagnetic metal billets using superconducting coils in a novel scheme is investigated.

The purpose of this paper is to analyze the influence of different parameters on the characteristics of the superconducting electrodynamic suspension (EDS) system.

The authors used an analytical model based on the dynamic circuit theory to perform the analysis. The authors proposed an inductance criterion to improve the calculation accuracy. They also proposed a three-dimension finite element method (FEM) to verify the validity of the analytical model.

The levitation force and guiding force increase with the superconducting magnet (SCM) speed and show a saturated trend, while the drag force decreases with the SCM speed. The vibration characteristic is the inherent characteristic of the superconducting EDS. The frequency and amplitude are affected by the gap between adjacent null-flux coils. The levitation force first increases and subsequently decreases with the levitation height. The total levitation force of the SCM increases with the superconducting coil (SC) number, while the average levitation force of an SC decreases with the SC number. The total levitation force nonlinearly increases with the SC number.

The authors introduced an inductance criterion for better understanding and using the analytical model, and they also proposed a 3D FEM method. The 3D FEM method could be extended to simulate the other EDS systems with more complex structures which the numerical model is no longer applicable. The results of the parameter study could deepen people’s understanding of EDS.

This study aims to reveal the room-temperature effect of a superconducting gravimeter prototype, which will guide its subsequent optimization to improve its gravimetric measurement accuracy.

Without leveling, the prototype output signal, tilt data and room temperature were measured under steady operating conditions. After analyzing the correlations of the three data sets, the residuals of the prototype’s output signal were compensated using the tilt data and the geodynamic effects (ocean tide loading, atmospheric loading and the gravitational effect of polar motion) were then corrected.

The remaining residuals after correction may be caused by small tilt variations that are due to the sensor chamber temperature and radiation shield temperature changes. These small tilt variations were submerged in the tilt signal noise. Although the peak-to-peak noise of the tiltmeter does not exceed 15 µrad, it can still produce gravimetric deviations above 60 µGal when the prototype is significantly tilted.

This study analyzes in detail the room-temperature effect of a superconducting gravimeter prototype, introduces the tilt effect of the relative gravimeters to compensate for the gravimetric deviations and emphasizes that the improvement of fine leveling and the accuracy of the tiltmeter are key requirements for the prototype to perform high-accuracy gravity measurement tasks.

The purpose of the paper is to provide a comparison of first‐ and second‐order two dimensional finite element models for evaluating the electromagnetic properties and calculating AC loss in high‐temperature superconductor (HTS) coated conductors.

The models are based on the two‐dimensional (2D) H formulation, which is based on directly solving the magnetic field components in 2D. Two models – one with a minimum symmetric triangular mesh and one with a single‐layer square mesh – are compared based on different types of mesh elements: first‐order (Lagrange – linear) and second‐order (Lagrange – quadratic) mesh elements, and edge elements.

The number and type of mesh elements are critically important to obtain the minimum level of discretization to achieve accurate results. Artificially increasing the superconductor layer and choosing a minimum symmetric mesh with triangular edge elements can provide a sufficiently accurate estimation of the hysteretic superconductor loss for a transport current.

This paper describes how the selection of mesh type and number of elements affects the computation speed and convergence properties of the finite element model using two different types of meshing. It offers an insight into the different factors modelers must consider when modeling HTS coated conductors and the methods that may be applied when extending the model to complex device geometries, such as wound coils.

An effective approach to the optimal design of electromagnetic devices should take into account the effect of mechanical tolerances on the actual devices performance. A possible approach could be to match a Pareto optimality study with a Monte Carlo analysis by randomly varying the constructive parameters. In this paper it is shown how such an analysis can be used to allow an expert designer to select among different Pareto optimal designs.

Field variations in the LHC superconducting magnets, e.g.during the ramping of the magnets, induce magnetization currents in the superconducting material, the so‐called persistent currents that do not decay but persist due to the lack of resistivity. This paper describes a semi‐analytical hysteresis model for hard superconductors, which has been developed for the computation of the total field errors arising from persistent currents. Since the superconducting coil is surrounded by a ferromagnetic yoke structure, the persistent current model is combined with the finite element method (FEM), as the non‐linear yoke can only be calculated numerically. The used finite element method is based on a reduced vector potential formulation that avoids the meshing of the coil while calculating the part of the field arising from the source currents by means of the Biot‐Savart Law. The combination allows the determination of persistent current induced field errors as a function of the excitation and for arbitrarily shaped iron yokes. The model has been implemented into the ROXIE program and is tested using the LHC dipole magnet as an example.

This paper deals with a model for the numerical calculations of thermal fields in superconducting a.c. magnet coils. The solution is based on Poisson's partial differential equation solved by the finite difference technique with the Guass‐Seidel (Liebmann) iteration method. The model contains numerical solutions for the magnetic field and calculations of heat losses generated by the coil winding. The computer program is briefly described and some results of calculations are presented.

To analyse the heating process of an aluminum billet rotating in a static magnetic field produced by superconducting coils.

The idea is to force the billet to rotate in a static magnetic field produced by a DC superconducting magnet. Since, a static superconducting magnet has no losses, the efficiency of the system is the efficiency of the motor used. In order to evaluate the temperature distribution arising from the field profile produced by a given coil configuration, a numerical model, based on an equivalent electric network with temperature‐dependent parameters, is used.

The main heating parameters, i.e. heating time, total power injected and temperature difference, are evaluated for different values of angular velocity and magnetic field. The field profile suitable to meet the specifics of an industrial heating process in terms of temperature homogeneity and heating time is determined. Starting form this profile the layout of the magnet is arrived at and some considerations on the operating condition of the superconducting windings are reported.

The mechanical stress in the billet due to weight, centrifugal effects, applied torque and resonance is examined by taking into account the weakening of the material properties with the increase of temperature and the practical limits of the heating process are evaluated.

DC induction heating of aluminum billet using superconducting magnets can be done fulfilling the specifics of the industrial processes.

A high‐efficiency induction heater for aluminum billets using superconducting coils in a novel scheme is investigated.

The purpose of this paper is to develop a rapid and realistic modelling approach for the design and characterization of high temperature superconducting (HTS) coils and windings carrying DC currents. Indeed, the strong dependence of the electromagnetic properties of such materials on the magnetic field makes the design and characterization of HTS systems a delicate operation where local quantities have to be evaluated.

A volume integral modelling approach has been developed taking into account the electric nonlinearity of the HTS material which is represented by power law. The variations of the characteristic quantities of the HTS (critical current density and power law exponent) with the magnetic flux density are also taken into account by using Kim’s law. The volume integral modelling allows to model only the active parts of the system and thus to overcome the difficulties linked to the multiscale dimensions.

The model has been tested in a case study in which simulation results were compared to measurements and to finite element analysis. A good agreement was found which validates the model as a rapid and efficient tool for HTS coils and windings design and modelling.

HTS coils are important elements of emerging superconducting devices which require a high level of reliability, such as generators or motors. The proposed approach is interesting to speed up the design and optimization procedures of such systems.

Advanced structures of the basic elements have been used in the volume integral modelling, which results in a considerable gain in computation time and in memory-space saving while keeping a high level of precision and realism of the modelling, which has been verified experimentally.