256 Ë 7 Numerical simulations of HTS MaglevFig. 7.25:Changing curve of the guidance forces on the HTSCs at a lateral displacement of 6 mm with
the growth of the total width. The total width is varied from 60 to 170 mm.at the position of 20 mm for both PMGs. The MLF even does not appear within our
selected range. This figure also indicates that the increase of the total width does not
always bring an enhancement of the levitation forces, especially for the case at a low
position. Of course, if a larger levitation capability is required at a higher position, it
is viable to lengthen the total width of the PMG. For the typical position of 15 mm in
the Maglev vehicle, the optimized value of the total width appears around 130 mm for
both PMGs because the slope of the curve begins to decrease at this value.
Fig. 7.25 shows the changing curve of the guidance forces at a lateral displacement
of 6 mm with the growth of the total width from 60 mm to 170 mm. From this figure,
it can be found that the guidance forces also increase firstly and then decreases with
the growth of the total width, and the maximum value of the guidance forces occurs
around 120 mm for Rail_A and around 135 mm for Rail_B. Although the total width
where the maximum value of the guidance forces occurs is scattered above Rail_A
and Rail_B, the variation of the guidance forces above both PMGs in the range of 120–
140 mm is not evident. Therefore this range can be considered as the optimized range,
which is comparable to the total width of the HTSC (126 mm), in determining the total
width of the PMG for a practical design.
The height of the PMG is another factor influencing the levitation capability of the
HTSC. Here, we fixed the width ratio to be 1 and total width to be 130 mm, and varied
the height of the PMG from 15 to 100 mm. The levitation forces above Rail_A and Rail_B
are plotted as a function of the height in Fig. 7.26. This figure clearly displays that no
matter the position where the HTSCs are, the levitation forces increase drastically at
first and then gradually saturates with increase in height of the PMG. This indicates