8.4 Some developed designs of the HTS Maglev vehicle system Ë 311Tab. 8.8:Calculated results of levitation force density.
Levitation gap (mm) 5 10 15 15
The T-shaped PMG(kg/m^3 ) 55,944 37,342 23,216 23,216
The present PMG (kg/m^3 ) 27,972 18,181 12,584 12,584
Tab. 8.9:Calculated results of guidance force density.
Lateral gap (mm) 5 10 15 15
The T-shaped PMG(kg/m^3 ) 51,748 27,972 16,783 8391
The present PMG (kg/m^3 ) 5874 3776 2797 2097
lift force compared to the present popular PMG. As listed in Tab. 8.9, the guidance force
density of the T-shaped PMG was much larger than that of the popular PMG. Especially,
at 5-mm lateral gap, the guidance force of T-shaped PMG was about 8.8 times larger
than that of the present popular PMG. The reason was mainly that the T-shaped PMG
had a strong periodic magnetic field in its upper space and strong symmetric magnetic
field in its lateral spaces.
8.4.3An asymmetric HTS Maglev curve design
Considering the attractive symmetric double-pole Halbach PMG (see Fig. 8.44 and
Section 8.4.1) for example, the effective magnetic circuit idea of the field potential
well was introduced with an asymmetric PMG design which produced the additional
guidance improvement especially for the HTS Maglev curve application.
From the view of the conventional considerations of the HTS Maglev system, the
double-pole Halbach PMG is regarded as a symmetric magnetic field source with the
line of symmetry atx=0 mm, as shown in Fig. 8.53a. This center line,x=0 mm, is also
the working line of symmetry of the on-board superconductor and the relative HTS
Maglev system. When the working center line is atx= −25 mm (x耠=0 mm, the peak
position ofBz), the applied magnetic field is asymmetric from the view of the working
center line, but a larger guidance force was obtained with the same 10-mm lateral
displacement of the HTS Maglev system. This is due to a effective magnetic circuit
design of the multi-pole PMG. Figure 8.53b shows a percentage increase of 84.5% when
x= −25 mm working as the center line compared with the case ofx=0 mm.
Figure 8.54 presents four asymmetric PMG designs and their magnetic field dis-
tributions which are evolved from two original optimized symmetric PMGs of PMG I
and PMG II. PMG I is the “Century” PMG type and PMG II is the Halbach PMG type.
Furthermore, combined with the asymmetric design of the PMG II (b) in Fig. 8.54, the