High Temperature Superconducting Magnetic Levitation

9.4 HTS FESS principle model Ë 351

Fig. 9.16:Upper part of HTS FESS model.

Fig. 9.17:Power generation demonstration of

the HTS FESS model.

of the FESS, the flywheel rotates with high speed and stores the electrical energy as
mechanical energy. The stored kinetic energy can be calculated asE=0.5Iw^2 , whereI
is the rotary inertia of the rotor andwis the rotational angular velocity. When the speed
is up to the maximum value of 13,000 rpm, the stored kinetic energy of the flywheel
model is about 9 kJ.
A set of control circuits, AC-DC converter, and a lamp load were used for the
power charge and discharge processes of the HTS FESS model. After the shaft levi-
tates, acceleration and deceleration of the flywheel rotor are realized by closing or
opening the switch of the circuit, thus realizing the charge and discharge of electrical
energy.
Figure 9.17 demonstrates the electricity generation after the speed of flywheel rotor
is up to 2000 rpm. When the acceleration of the FESS is finished, by switch from the
driving circuit of the motor to the load circuit, the motor will run as a generator, and
then the stored energy of the flywheel rotor will be released to the lamp load. This
12-V/10-W lamp is lit for ten of seconds, as shown in Fig. 9.17. The lighting of the lamp
illustrates the whole energy storage and conversion of the FESS system from electricity
energy to mechanical energy and then mechanical energy back to electricity energy
intuitively.