10.6 Studies on HTS linear synchronous motor Ë 377Fig. 10.3:Top view of the HTS REL system (W. Liu, J.S. Wang, G.T. Ma, et al., unpublished data).
signal of projectile to part 7, the electromechanical switching. Part 6 is the HTS
projectile.
As Fig. 10.3 shows, only parts 2 and 4 segments were used to accelerate the
projectile, which was significant in reducing the cost of the propulsion system. The
difficult technology of this system was the AC power supply for the propulsion coils.
For example, if the required muzzle velocity was 10 km/s, the pole pitch of the linear
motor was 0.1 m, and then the synchronous frequency of linear motor was 50 kHz. For
an inverter based on variable voltage, variable frequency technology, it was assumed
that the carrier wave ratio was 20 and that the switching frequency of the power
electronics component was 1 MHz, which was difficult to achieve especially under the
high power level.
For this particular application, there are still some problems need to be solved.
One is the huge electromagnetic stress produced by the large magnetostatic field
of the balance coils and the supercurrent in the propulsion and balance coils. This
huge electromagnetic stress may cause serious damage to the braced structures.
Another problem is the large centrifugal force on the projectile, which can lead to
serious overload and possible damage to the folding antennae, guided device, airfoil,
inflatable structure etc. It is necessary to design the launch rings with a large enough
diameter to reduce the damage from overload.
10.6 Studies on HTS linear synchronous motor
Linear synchronous motor (LSM) is the common drive system to a Maglev train. The
on-board LSM motor may constitute nearly one third of the total weight of a Maglev