A fully superconducting bearing system for flywheel applications

Xu, Kun; Wu, Dong-jie; Jiao, Yu; Zheng, Minghui

doi:10.1088/0953-2048/29/6/064001

Cited by 28 publications

(13 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main challenge in performing spin-down tests is to engineer a driving system to accelerate and decelerate the levitating PM. Gas jets [10,22], electrical motors [10,[23][24][25], a three-phase handmade brushless motor [26], eddy current clutches [15,23,[27][28][29][30], and magnetic gears [31] have been employed to accelerate the rotating part of superconducting bearings. These methods are associated with complex coupling structures, loss creation, limited maximum speed, and lack of precision when it comes to speed control.…”

Section: Introductionmentioning

confidence: 99%

Design, Build, and Evaluation of an AC Loss Measurement Rig for High-Speed Superconducting Bearings

et al. 2022

View full text Add to dashboard Cite

Friction and heat generated in conventional bearings impose a limit on maximum design speed in electrical machines. Superconducting bearings offer the potential for low loss, simplified, and passively stable bearings that can overcome the speed limit and operate at high loads. Although such bearings are contactless and seem to be loss free, AC loss mainly caused by magnetic field inhomogeneity gradually slows down the rotating body. This loss, whose mechanism has not been fully explored, is measured through spin-down tests where the rotational speed of the spinning rotor is measured as a function of time. However, there are some challenges in performing a reliable spin-down test. In this paper, we discuss these challenges as well as the engineering of an experimental test rig that enables us to spin-up, release, and recapture the levitated permanent magnet. We also discuss the specifications of the driving mechanism including the self-aligning coupling, which accommodates permanent magnets of different sizes. Initial test results at 6600 rpm are discussed and further technical improvements to the test rig suggested. This rig will be used as a key tool to explore the AC loss mechanism and inform the design of bearings for high-speed superconducting machines.

show abstract

Section: Introductionmentioning

confidence: 99%

Design, Build, and Evaluation of an AC Loss Measurement Rig for High-Speed Superconducting Bearings

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The high-speed levitation system based on permanent magnets (PMs) and bulk high-temperature superconductors (HTSs) has demonstrated the tremendous potentials in several fascinating applications, such as superconducting maglev vehicles [1][2][3][4][5], linear synchronous motors [6][7][8], and superconducting flywheel energy storage systems [9][10][11]. Because of its competitive features like self-stability without energy input, being free from mechanical friction, and no need for active control system, research on levitation force and guiding force of superconducting levitation system has been studied [12,13], and however, behaviors of bulk HTSs in an alternating magnetic field (AMF) will affect the performance of the superconducting levitation system.…”

Section: Introductionmentioning

confidence: 99%

“…Bulk HTSs (2) are fixed in the copper ring (1), which constitute a stator of the HTS bearing. Structure of the HTS flywheel can be referred [20]. Rotor of the flywheel system can be levitated once it is moved up and down due to the flux pinning effect of bulk HTSs.…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis on temperature characteristics of a rectangular bulk YBCO exposed to alternating magnetic field

et al. 2019

View full text Add to dashboard Cite

The motion of magnetic flux will cause temperature rise inside of a bulk high-temperature superconductor (HTS) when exposed to an alternating magnetic field (AMF). In levitation system, like superconducting motors, bearing and vehicle, however, bulk HTSs are always subjected to ripple fields due to mechanical vibration, as well as harmonic field of armature windings, which will cause energy loss inside of bulk HTSs. Part of the heat caused by the energy loss is transferred to liquid nitrogen (LN 2) through the surface of bulk HTSs, and the other part will lead to temperature rise inside bulk HTSs. We experimentally analyzed the temperature characteristics of bulk YBCO under different AMF frequencies in this article. And the effect of AMF on the temperature rise of the bulk HTS under different cooling heights (CHs) and working heights (WHs) was also studied. The results showed that the higher the CH, the greater the temperature rises inside the bulk HTS. Besides, the temperature of the whole bulk HTS increases with the decrease in the WH and the increase in AMF frequency. The results and analyses of this article are useful for the application of bulk HTSs in the high-speed rotating and transportation systems.

show abstract

“…Potential applications of bulk HTS include high-magnetic-field permanent magnets, magnetic bearings, magnetic separators and levitated transportation systems [2][3][4][5]. Over the past thirty years, therefore, there has been a concerted effort world-wide to develop these materials for practical applications [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

A novel pre-sintering technique for the growth of Y–Ba–Cu–O superconducting single grains from raw metal oxides

Shi

Dennis

et al. 2017

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Most established top seeded melt growth (TSMG) processes of bulk, single grain Y-Ba-Cu-O (YBCO) superconductors are performed using a mixture of pre-reacted precursor powders. Here we report the successful growth of large, single grain YBCO samples by TSMG with good superconducting properties from a simple precursor composition consisting of a sintered mixture of the raw oxides. The elimination of the requirement to synthesize precursor powders in a separate process prior to melt processing has the potential to reduce significantly the cost of bulk superconductors, which is essential for their commercial exploitation. The growth morphology, microstructure, trapped magnetic field and critical current density, J c , at different positions within the sample and maximum levitation force of the YBCO single grains fabricated by this process are reported. Measurements of the superconducting properties show that the trapped filed can reach 0.45 T and that a zero field J c of 2.5 × 10 4 A cm −2 can be achieved in these samples. These values are comparable to those observed in samples fabricated using pre-reacted, high purity commercial oxide precursor powders. The experimental results are discussed and the possibility of further improving the melt process using raw oxides is outlined.

show abstract

A fully superconducting bearing system for flywheel applications

Cited by 28 publications

References 11 publications

Design, Build, and Evaluation of an AC Loss Measurement Rig for High-Speed Superconducting Bearings

Design, Build, and Evaluation of an AC Loss Measurement Rig for High-Speed Superconducting Bearings

Experimental analysis on temperature characteristics of a rectangular bulk YBCO exposed to alternating magnetic field

A novel pre-sintering technique for the growth of Y–Ba–Cu–O superconducting single grains from raw metal oxides

Contact Info

Product

Resources

About