scholarly journals Effect of combining a DC bias current with an AC transport current on AC losses in a high temperature superconductor

1999 ◽  
Vol 9 (2) ◽  
pp. 1065-1068 ◽  
Author(s):  
P. Dolez ◽  
B. Des Ligneris ◽  
M. Aubin ◽  
Wen Zhu ◽  
J. Cave
Keyword(s):  
High Temperature ◽  
High Temperature Superconductor ◽  
Bias Current ◽  
Transport Current ◽  
Ac Losses ◽  
Dc Bias

scholarly journals Measurements and Analysis of AC Losses in HTS Windings of Electrical Machine for Different Operation Modes

2021 ◽  
Vol 11 (6) ◽  
pp. 2741
Author(s):  
Sergey Zanegin ◽  
Nikolay Ivanov ◽  
Vasily Zubko ◽  
Konstantin Kovalev ◽  
Ivan Shishov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
High Temperature Superconductor ◽  
High Temperature Superconductors ◽  
Transport Current ◽  
Operating Conditions ◽  
Ac Losses ◽  
Electrical Machine ◽  
2Nd Generation ◽  
Motor Mode

The article is devoted to the study of losses in devices based on high-temperature superconductors of the 2nd generation. The complexity of the devices under study increases from a single rack coil to a winding assembled from several coils, and finally to an electric machine operating in generator mode. This is the way to experimentally study the behavior of 2nd generation high temperature superconductor (2G HTS) carrying a transport current in various conditions: self-field, external DC, and AC magnetic field. Attention is also paid to the losses in the winding during its operation from the inverter, which simulates the operating conditions in the motor mode of a propulsion system.

Study on Minimum Propagation Current of Bi-2223/Ag Superconducting Multifilament Tape

2007 ◽  
Vol 546-549 ◽  
pp. 1985-1988
Author(s):  
Zhi Ming Bai ◽  
Chun Li Wu ◽  
Hai Liang Yang ◽  
Jin Xing Wang
Keyword(s):  
High Temperature ◽  
High Temperature Superconductor ◽  
Operating Temperature ◽  
Experimental System ◽  
Transport Current ◽  
Background Magnetic Field ◽  
Multifilament Tape ◽  
Gas Cooling ◽  
Quench Propagation ◽  
Simulated Calculation

Minimum propagation current of Bi-2223/Ag superconducting multifilament tape was studied in detail, including experimental investigation and numerical calculation using finite element method (FEM). A set of experimental system has been established, quench propagation velocities with various transport current have been measured and minimum propagation current has been obtained in the condition of N2 gas cooling. The effect of parallel background magnetic field on minimum propagation current has also been studied experimentally. In addition, minimum propagation current at different operating temperature has been gained by the simulated calculation using FEM.It has been found that the high temperature superconductor is stable if only transport current is smaller than minimum propagation current of the time no matter what condition it is in. Minimum propagation current can be considered as an important stability criterion of high temperature superconductor.

Overview of High Temperature Superconductor Machines

2021 ◽  
Vol 4 (4) ◽  
pp. 25-33
Author(s):  
Bruno Douine ◽  
◽  
Hocine Menana ◽  
Kevin Berger ◽  
Jean Lеvеque ◽  
...  
Keyword(s):  
High Temperature ◽  
Power Systems ◽  
High Temperature Superconductor ◽  
High Temperature Superconductors ◽  
Synchronous Machine ◽  
Recent Time ◽  
Operating Principle ◽  
Electrical Machines ◽  
Synchronous Machines ◽  
Ac Losses

Electrical machines are important parts of different power systems. The application of high temperature superconductors (HTS) in electrical machines is very promising due to high transport currents. This paper reviews various topologies of superconducting motors and generators using HTS published in the literature in recent time. It begins with a brief presentation of the HTS material used in electrical machines. The description of AC losses and cryogenic systems is done afterwards. Then we offer a striking description of the various realizations of HTS electrical machines such as half HTS synchronous machines, fully HTS synchronous machine, machines with HTS bulks and stacks. Some of these machines are totally innovative compared to conventional ones and their operating principle is strictly related to the presence of HTS materials.

scholarly journals AC losses of no-insulation high temperature superconductor (RE)Ba2Cu3Ox coils induced by ripple magnetic fields in machines

2020 ◽  
Author(s):  
Yawei Wang
Keyword(s):  
High Temperature ◽  
Magnetic Fields ◽  
High Temperature Superconductor ◽  
Eddy Currents ◽  
Ac Loss ◽  
Ac Losses ◽  
Induced Current ◽  
Risk Optimization ◽  
Current Flows ◽  
The Stability

<p>No-insulation high temperature superconductor (NI HTS) (RE)Ba2Cu3Ox coil technology is effective in enhancing the thermal stability of HTS coils. Applying the NI technique on the rotor windings of HTS machines can improve the stability and reliability of the machines. However, the NI HTS rotor windings experience ripple magnetic fields, which leads to induced eddy currents through the turn-to-turn contacts. The accompanying turn-to-turn losses will considerably affect the machine efficiency. In this study, we compared experimentally the losses of NI HTS coils subjected to external AC magnetic fields with those of insulated coils. Measurement system based on calibration-free method is developed for the AC loss measurement on HTS coils exposed to external AC magnetic fields. The results show that the AC loss of NI HTS coils can be 20 times higher than that of insulated HTS coils, and lowering turn-to-turn resistivity can significantly reduce this AC loss. Modeling analysis shows that most of induced current flows in the outer turns of the NI HTS coil because of skin effect, and lower turn-to-turn resistivity leads to higher induced current in superconducting layers and more significant accumulation of turn-to-turn loss. This will increase quench risk. Optimization of turn-to-turn resistivity is required when the NI HTS coil is applied in the machines environments. </p>

scholarly journals Levitation and Lateral Stabilization Device Based on a Second-Generation High-Temperature Superconductor

2019 ◽  
Vol 5 (4) ◽  
pp. 115-123
Author(s):  
Yuri F. Antonov
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
High Temperature Superconductor ◽  
Second Generation ◽  
Permanent Magnets ◽  
Transport Current ◽  
Critical Parameters ◽  
Technical Solution ◽  
The Magnetic Field ◽  
Superconducting Levitation

The superconducting levitation device comprises a stationary magnetic rail of permanent magnets and a cryostat on a vehicle with a second-generation high-temperature tape superconductor placed in the cryostat, folded in a stack or wound by a coil on a non-magnetic frame without electrical connection of the ends and the transport current. Cool tape high-temperature superconductor of the second generation, folded in a stack or wound on a non magnetic frame in the form of axisymmetric or track coil, without electric connections of the ends and a transport current, behaves as a massive sample of a superconductor and the Meissner Oxenfeld effect, the magnetic field created by the magnetic rail is displaced from the volume of the superconductor, causing the power of levitation and the vehicle hangs over the track structure. The high critical parameters of the second-generation high-temperature superconductor belt ensure efficient operation of the superconducting levitation device. Aim: To demonstration the technical feasibility and efficiency of creating a levitation unit based on the use of a second-generation high-temperature superconductor and permanent magnets made of rare earth metals. Methods: Calculations of the magnetic field distribution in the combination of a magnetic rail and a massive superconductor, preliminary design of the levitation unit and experimental studies on the model. Results: Experiments on a model of a superconducting levitation device confirmed the efficiency of this technical solution and its effectiveness. Conclusion: an original technical solution is proposed that allows to significantly improve the energy characteristics of the levitation node by using a second-generation high-temperature superconductor operating in a passive mode without a transport current, using the partial Meissner-Oxenfeld effect and the engagement of quantized magnetic flux strands at the pinning centers.

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