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Pan S.T.,Southwest Jiaotong University | Wang S.Y.,Southwest Jiaotong University | Wang S.Y.,National Laboratory of Rail Transit | Jiang D.H.,Southwest Jiaotong University | And 2 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2011

In the application of high temperature superconducting (HTS) magnetic levitation (maglev) system under vertical inclination of permanent magnetic guideway (PMG), the component of the total weight of levitation body above the PMG will be changed. Therefore, the influence of the vertical inclination of PMG on levitation characteristics of HTS maglev system cannot be ignored, such as the levitation gap, the levitation force, guidance force and driving force of the linear motor. In order to investigate the influence of the vertical inclination angle on levitation characteristics of the HTS maglev system, a HTS maglev launch platform has been designed and fabricated for the investigation the influence of vertical inclination angle between the range of 0° and 18° on the levitation and guidance and driving force parameters of the HTS maglev launch platform. Experimental results show that the levitation gap was the main levitation characteristic for HTS maglev system under vertical inclination of PMG, which increased with increment of the vertical inclination angle. However, the levitation force, and the driving force of the linear motor decreased. The guidance force could not be influenced by the increment of levitation gap. The experimental results are helpful toward improving the running performance of the HTS Maglev launch system. © 2010 Springer Science+Business Media, LLC. Source

Deng Z.,Southwest Jiaotong University | Zheng J.,Southwest Jiaotong University | Zheng J.,National Laboratory of Rail Transit | Lin Q.,Southwest Jiaotong University | And 7 more authors.
Journal of Low Temperature Physics | Year: 2011

Zero-field cooling (ZFC) and field cooling (FC) are the two most popular activation ways of the bulk high-temperature superconductors (HTSCs). The former can bring a big levitation force but a poor stability, while the latter can bring a good stability but a reduced levitation force due to the trapped flux. Under this rule, it is very difficult to improve the levitation force (load capability) and guidance force (stability) at the same time with the given bulk HTSCs and applied field in practice. In the paper, based on the re-magnetization ability of bulk HTSCs, the maglev performance of bulk HTSCs with a re-magnetization process after ZFC was experimentally investigated above a permanent magnetic guideway (PMG). The bulk HTSCs were firstly cooled down at a far distance above the PMG, but before moving to the working height, an additional process was introduced to descend the bulks to a lower height to magnetize again by the PMG field. Experimental results show that, at certain remagnetization height above PMG, the levitation force and guidance force could be improved simultaneously compared with the results of normal FC cases, which is different from the present performance improvement with the sacrifice of one important force. This result presents a possible working way for the levitation applications of bulk HTSCs by employing a re-magnetization process after ZFC, and is also useful to optimize the performance of high-temperature superconducting Maglev vehicle systems. © Springer Science+Business Media, LLC 2010. Source

Deng Z.,Southwest Jiaotong University | Zheng J.,Southwest Jiaotong University | Zheng J.,National Laboratory of Rail Transit | Lu Y.,Southwest Jiaotong University | And 6 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2010

As the basic parameter in the design of high-temperature superconducting (HTS) magnet levitation (maglev) vehicle system, the levitation force data are usually obtained by experiments, so a reliable measurement method is needed to know the practical levitation force of onboard bulk superconductor. Considering in the actual operation the vehicle will experience some small vertical or lateral movements, especially during the passenger going on or off the vehicle, the usual measurement method for levitation force, in which force with gap and force relaxation are measured, cannot be able to predict the levitation force change due to the vertical or lateral movements. So a measurement method is presented regarding effects of force with gap, relaxation, vertical and lateral movements. Compared with a former measurement method, the presented method may support more reliable levitation force data for the HTS maglev vehicle design. © 2010 Springer Science+Business Media, LLC. Source

Wang W.,Southwest Jiaotong University | Wang W.,National Laboratory of Rail Transit | Wang J.,Southwest Jiaotong University | Wang J.,National Laboratory of Rail Transit | And 6 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2010

The forcespeed relationship of a bulk YBCO moving above a permanent magnetic guideway was studied. The experiments show that the levitation forces at the lowest position Fmax increase with the increment of descending speed and tend to approach a certain levitation force FS.max. Calculations based on a simplified superconducting ring and flux flow model show that the force variations can be ascribed to the resistive electric field produced by flux motion. Further calculation reveals that, by increasing the descending speed, the thermo-dissipation inside the superconducting ring immediately after the descending process exponentially declines, approaching zero while the speed approaches infinity, and Fmax reaches F S.max. Therefore, the thermo-dissipation inside the bulk YBCO can be defined as a parameter for evaluating levitation force losses. Those results might be useful in pragmatic design of high-Tc superconducting levitation devices and magnetization of type-II superconductors. © 2006 IEEE. Source

Zheng J.,National Laboratory of Rail Transit | Zheng J.,Southwest Jiaotong University | Deng Z.G.,National Laboratory of Rail Transit | Deng Z.G.,Southwest Jiaotong University | And 9 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2010

An asymmetrical permanent magnet guideway (PMG) design is considered for the high temperature superconducting (HTS) Maglev during traveling on a curved path. This translationally asymmetrical PMG design can produce a better guidance performance, which cannot be provided by the common translationally symmetrical PMG design. The additional guidance improvement is attributed to its asymmetrical magnetic field distribution. The outside part of the asymmetrical PMG has more magnetic material than the inside part, so that the outside magnetic field density is enhanced or becomes a multi-pole distribution. These two effects result in a larger guidance force and a better curve negotiation ability. Above the asymmetrical curved PMG, the HTS Maglev vehicle system can overcome larger centrifugal forces and run with a smaller or even zero lateral displacement. Moreover, this asymmetrical PMG design is helpful to realize the "straight line to curve to straight line" running environment. The improvement effect and running feasibility of the asymmetrical PMG is calculated and proven for future use in HTS Maglev curves. © 2010 Springer Science+Business Media, LLC. Source

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