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As an important research topic of ship electric propulsion and new power generation, high-temperature superconducting (HTS) machines have become a research hotspot in the field of HTS applications in recent years. With high power density, high efficiency, and outstanding dynamic characteristics, HTS motors could bring much more great social and economic benefits. Meanwhile, the application conditions of HTS materials are harsh, and any parameters of the HTS materials beyond the safe range of operation are probable to lead the HTS materials to quench. The quenching of HTS materials changes the state parameters of power devices; what's more, it will bring a huge impact on the safety and stability of HTS power system. To ensure the safe operation of the HTS machine, by detecting the voltage, environment temperature, and liquid nitrogen level, this paper designed a wireless online monitoring system to determine whether the HTS material has failed. The system is based on the brief principle of superconductor quench. In addition, the system was applied to a 500-kW HTS power generator. The experiment shows the sufficient accuracy and reliability of the wireless online monitoring system. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) machines have the virtues of higher power density and better stability, which makes it a good prospect in the applications of wind power generation and ship propulsion. When the high-temperature superconductor is used in the rotating machines, the behavior of the conductor would be affected by the complex magnetic field, Lorentz force, and the centrifugal force. In order to evaluate the performance of the HTS coil in the machine, a finite element method model of the machine to calculate the magnetic field coupled with stress field was built in this paper. At first, the distribution of the magnetic field in the machine was calculated, then the Lorentz force was calculated and transferred to the stress field to obtain the stress and strain in the HTS and other structural materials. In the calculation, three operating conditions were considered, including no-load, full-load, and three-phase short-circuit fault. The results show that the stress on the HTS coil and the structural component are all smaller than the critical stress, which proves that the design is reliable. [ABSTRACT FROM PUBLISHER]

This paper proposes a new kind of racetrack-shaped high-temperature superconducting (HTS) magnet for a stator field-excitation HTS machine, for the purpose of implementing stationary seal at the cooling Dewar. The key is to introduce a vacuum sandwich-structure into the proposed racetrack-shaped Dewars so that the operation temperature of field-excitation windings can be regulated at 63 K. The method of reducing pressure by vacuuming is applied accordingly to decrease the temperature of cryogenic liquid nitrogen to ensure the cooling effect. The test results show that all the fabricated racetrack HTS magnets can operate at HTS state when the excitation current reaches 40 A. Hence, the proposed racetrack HTS magnet is experimentally verified. [ABSTRACT FROM PUBLISHER]

Abstract: This paper describes Superwind HTS machine laboratory setup which is a small scale HTS machine designed and build as a part of the efforts to identify and tackle some of the challenges the HTS machine design may face. One of the challenges of HTS machines is a Torque Transfer Element (TTE) which is in this design integral part of the cryostat. The discussion of the requirements for the TTE supported with a simple case study comparing a shaft and a cylinder as candidates for TTE are presented. The discussion resulted with a cylinder as a TTE design rated for a 250Nm and with more then 10 times lower heat conduction compared to a shaft. The HTS machine was successfully cooled to 77K and tests have been performed. The IV curves of the HTS field winding employing 6 HTS coils indicate that two of the coils had been damaged. The maximal value of the torque during experiments of 78Nm was recorded. Loaded with 33%, the TTE performed well and showed suffcient margin for future experiments. [Copyright &y& Elsevier]

In this paper, a new linear stator permanent magnet (PM) vernier high-temperature superconductor (HTS) machine is proposed for wave energy conversion. The machine adopts a double-sided design and inner-translator arrangement where the stator consists of two plane iron cores with salient teeth wound with 3-phase armature windings and PMs mounted on the surface of the stator teeth. While the translator is designed as an iron core with salient teeth on the two sides, the HTS bulks are inset between every two adjacent salient teeth to shield the flux leakage, thus improving the power density of the machine. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed. Also, the proposed machine is quantitatively compared with the existing linear stator PM vernier machine. Hence, it validates that its performance, especially the power density, can be improved significantly. [ABSTRACT FROM PUBLISHER]

In order to design a High Temperature Superconducting (HTS) machine that is able to operate safely and reliably, studies on the characterization of Second Generation (2G) HTS tapes are of paramount importance. This paper presents an experimental setup to measure critical current of 2G HTS tapes in high DC magnetic fields (up to 5 Tesla) with an AC current ripple superimposed, as well as various temperatures ranging from 25 K to 77 K. The 2G tape measured is the SGS12050 coated conductor made by SuperPower. The critical current is measured by a flux vector with reference to the widest sample face from 0 to 90 degrees in 10 degree steps. Smaller steps are required close to 0^\circ. A Variable Temperature Insert (VTI) is utilized to control temperature change. [ABSTRACT FROM AUTHOR]

This paper proposes a linear doubly-salient high-temperature superconductor (HTS) machine for wave energy conversion, which is composed of a tubular stator and a tubular translator. Since the translator is a simple iron core with salient poles, it is so robust that it can be directly coupled with the reciprocating buoy. The stator consists of an iron core with salient poles, DC HTS field windings and 3-phase HTS concentrated armature windings. By using the finite element analysis, the proposed machine is quantitatively compared with its permanent magnet and copper-winding counterparts. Hence, it validates that its performance, especially the power density, can be improved greatly. [ABSTRACT FROM AUTHOR]

• Output power of 3 kW is reached for fully superconducting machine • Full design process of 3 kW fully HTS machine is described. • Comparison of analytical, finite element modeling and experimental results of 3kW HTS machine is provided. Good agreement between results is achieved. Superconducting (SC) electrical machines could affect different industries due to their high power density. The most promising of them are fully superconducting machines. In the paper whole cycle of development of fully high temperature superconducting electrical machine is described: analytical calculation of magnetic field in the active zone of the machine, finite element modeling, some design features and experimental research of small-scale prototype. It is shown that theoretical and experimental results are in good correlation. Developed approaches could be used to develop high-power machines. [ABSTRACT FROM AUTHOR]