186 Ë 6 First manned HTS Maglev vehicle in the world
Fig. 6.41:A scheme for Maglev vehicle
system using the HTS bulk and the
electromagnets [48]. (1) Induction plate.
(2) Induction motor stator. (3) HTS Bulks.
(4) Slide for landing. (5) Electrical magnets.
(6) Road pier. (7) Vessel of liquid nitrogen.bulks can trap enough flux to become a new PM. The HTS PMs have a much higher
energy product than the rare-earth PMs, and their potential industrial applications
are very promising. The HTS PMs can realize an energy product of l.8 MJ/m^3 [50].
This value is 3.5 times higher as NdFeB. The maximum trapped fieldB 0 is 17.24 T in
a bulk YBCO sample of 2.65 cm diameter at 29 K [51]. A production run of 60 melt-
textured YBCO trapped field magnets, 2 cm in diameter, was recently reported by
Sawh et al. [52] The resulting average trapped field at the center of the seed-side
surface was 2.04 T at 77 K. It can also be applied to EMS systems because of the
simple structure and large levitation forces that can be obtained. Figure 6.42 shows
a full-superconducting scheme with HTS PMs [48]. In Fig. 6.42, the control coils are
attached to the bulk superconductors bathed in liquid nitrogen. When the trapped
field of the HTS PMs is changed by inherent or external fluctuations, the field change
can be compensated by the control coils. The coils of the LSM are used for the
propulsion. The special geometry of the liquid nitrogen vessel containing the bulk
superconductors is designed for exciting the field. It is very important for the HTS PMs
to excite the field. The applied magnetic field is not only high, but also both its size
and orientation are restricted.
Another scheme for a Maglev vehicle system using the HTS PMs is shown in
Fig. 6.43 [48]. This scheme requires that the HTS PMs have very high performance. The
HTS PMs play the role of the suspension, the propulsion, and the guidance. The HTS
Fig. 6.42:Scheme A for Maglev vehicle
systems using HTS PMs [48]. (1) HTS PMs
for LSM. (2) Coil of LSM. (3) HTS PMs for the
suspension. (4) Slide for landing. (5) Iron
guideway. (6) Road pier. (7) Control coil.
(8) Vessel of liquid nitrogen.