Optimized Design of 8-Figure Null-Flux Coils in EDS Maglev.
The 8-figure null-flux ground coils in EDS (Electro-Dynamic Suspension) including the PLG (combined Propulsion, Levitation and Guidance) system, which can both suspend and propel maglev vehicles simultaneously, have mainly longitudinal and vertical dimensions such as coil pitch and heights of upper and lower coils. In this paper we investigate these dimensions not only to balance the basic performance for levitation, guidance and propulsion, but also to reduce magnetic disturbance of superconducting magnet. By using an optimization program, we induced the relationship between the basic performance and these dimensions. Furthermore, by implementing a modal analysis, we predicted the vibration of superconducting magnet in different pitches, and thereby proposed these dimensions to decrease the vibration.
ELECTRODYNAMIC GENERATOR OF GRAVITY SENSATION
Rotation is in the focus of all artificial-gravity research as centripetal acceleration generated by rotation can be substitute for gravity. A very effective way to spin an object in space is to use electrodynamic technologies and obtain controlled rotation of habitats for generating gravity sensation by means of guidance and velocity control by a unified trajectory control system made of propulsion and steering subsystems. Superconducting electrodynamic technologies are especially suitable to be optimized and applied in space. Deep space, as cold vacuum without gravity, offers significant advantages for application of electrodynamic technologies. 1 SUPERCONDUCTING ELECTRODYNAMIC TECHNOLOGY APPLIED IN SPACE Electrodynamic technologies based on repulsive forces use powerful superconducting magnets to obtain gaps large enough to enable their use in circular paths. Electrodynamic systems are stable and there is no need for active electronic stabilization. Superconducting Japanese EDS (electrodynamic suspension) Maglev (magnetic levitation) trains technology in which vehicle is suspended, guided and propelled by magnetic forces and fields, is suitable to be optimized and applied to spin an object in space by contolled rotation.
Electromagnetic Vibration Heat Load of Superconducting Magnets for Maglev Train
Superconducting magnets on Maglev trains vibrate due to harmonic ripples of electromagnetic flux generated by ground coils. Heat load caused by vibration in the magnet, made in 1990, amounted to several tens of watts in the electromagnetic vibration test. This was mainly because AC loss was induced in the helium vessel housing the superconducting coil, due to relative vibration between the aluminum thermal shield and the coil. The heat load caused by vibration should be strictly restricted to less than 4W due to limited cryogenic refrigeration capacity. The heat load has been tested using electromagnetic flux ripples for a superconducting magnet model of one coil which corresponds to 1/4 of an actual magnet. The flux ripples simulate the 6th harmonic of the actual ground levitation coil. Some ideas to reduce the heat load were tried for the magnet model, such as high resistance thermal radiation shield, high rigidity of vacuum vessel, high purity copper plating on the helium vessel. As a result, these ideas were effective, and the maximum heat load due to vibration was restrained to less than 4W per magnet for one coil magnet model.