246 Ë 7 Numerical simulations of HTS Maglev
Fig. 7.19:Normalized maximum levitation forces with the ratio of height to width of the PMG.
In order to clearly show the relationship between the ratio of TD to TB of the PMG and
the MLF of the HTSC, the curve of the normalized MLF with respect to the ratio of TD
to TB is shown in Fig. 7.19. It is clear that when the ratio of TD/TB<1, which we call
ultra-wide, the MLF will decrease with increasing TD/TB. When the ratio of TD/TB>1,
which we call ultra-height, the MLF will increase with increasing TD/TB. It should
be noticed that when increasing the cross section of the PMG while keeping the ratio
of TD/TB constant, also increases the MLF simultaneously. This will, however, cause
increase of the cost of the PMG.
From Fig. 7.19, we see that in the ultra-wide case, when the ratio of TD/TB changes
from 1.0 to 0.95, the MLF changes faster compared to changing the ratio from 0.95 to
0.6. Similarly, prerequisite of ultra-height, when the ratio of TD/TB changes from 1.0
to 1.05, the MLF changes faster, compared with changing the ratio from 1.05 to 1.6. The
shaded region in Fig. 7.19 may be effective in lowering the cost of the levitation parts.
On the basis of the discussions presented above, we can conclude that for HTS
Maglev vehicle using a monopole PMG, low-levitation-cost optimization way can be
achieved by utilizing a PMG whose ratio of height to width fulfils
TD/(TB+TB)⊆( 0. 475 , 0. 525 ). (7.63)
7.6.2Tmethod [10]
7.6.2.1Mathematical fundamentals
TheTmethod referred here is an extended version of the traditionalT-Ωmethod,
which was proposed by Miya and coworkers [47] to calculate eddy-current problems
and was adapted in recent years to electromagnetically model the HTS Maglev in 3D