Driving dynamics of large scale superconducting MagLev systems

Besides the zero-resistivity below a critical temperature, high temperature superconductors (HTS) show a very special behavior in an external magnetic field. The magnetic field penetrates the material in form of magnetic flux lines which can be immobilized (pinned) by nanometer scale defects in the material. If the superconductor is deflected from its original position in a magnetic field, this pinning mechanism leads to reset forces which restore the superconductor’s original position. These reset forces enable a stable contactless levitation of a superconductor in a magnetic field, which is impossible for any arrangement of permanent magnets, soft magnets or electromagnets.
For industrial applications of superconducting magnetic bearings it is necessary to increase the pinning force in the superconducting material. Melt-textured bulk YBa2Cu3O7-X (YBCO) is the most promising composition to fulfill this requirement. The fabrication method of melt texturing of YBCO bulks has been optimized at the IFW Dresden.
The phenomenon of stable levitation of a type II superconductor in a magnetic field opens a wide field for future applications for all different kinds of linear or radial magnetic bearings. The main advantages of such bearings are their vanishing small mechanical friction and their soft suspension, which lead to smaller energy consumption and longer durability of all system components when compared to conventional bearings. If the magnetic field is provided by permanent magnets or a combination of soft and hard magnetic materials, no controlling system of the levitation is required. Apart from the cooling system there is no additional power consumption.
Magnetic bearings without mechanical friction are not only useful to support rotating machinery but also for systems with lateral motion such as transport systems. Lateral motion requires a magnetic track which provides on the one hand side a magnetic field profile which is homogeneous along the track direction and on the other hand side a strong field gradient perpendicular to the track direction. A superconducting magnetically levitated passenger train can take advantage of all the mentioned features and can bring this advanced new technology to the people as a kind of a fascinating traveling experience in an energy saving, environmental friendly, fast and effective transport system.