350 Ë 9 HTS Maglev bearing and flywheel energy storage system
Fig. 9.15:Photo of PM rotor of ASB.is 0.4 T. Two in-house epoxy fiberglass Dewars are used as the holder and cryostat for
the YBCO bulks. Those two Dewars are with outer diameter of 140 mm and height of
75 mm and the thickness of wall is only 2 mm. Eventually, the double ASBs can provide
a levitation force of 79.2 N and a lateral force of 9.7 N at the lateral displacement of
3 mm under a certain working condition [58].
9.4.4FESS model with double ASBs
The HTS FESS model is mainly composed of the double ASBs, flywheel rotor, PM
motor, and a set of control circuit. Table 9.5 gives the detailed parameters of this HTS
FESS model.
The motor employed in this system is a PM motor which is brushless and can
work as a generator. The rated three-phase voltage of the motor is 380 V, the rated
efficiency 95.8%, the maximum speed 13,000 rpm, and the air gap is 1.5 mm. The PM
motor is mounted at the middle of the FESS model and controlled by a frequency con-
verter to study the rotational characteristics of the rotor under different acceleration
models.
A steel disk with diameter of 200 mm, weight of 1.4 kg, and rotary inertia of
0.01 kg/m^2 is used as the flywheel of the HTS FESS model. The flywheel is installed
between the PM motor and the upper SMB, as shown in Fig. 9.16. As the energy carrier
Tab. 9.5:Parameters of the FESS model with double ASBs.
Stored energy 9 kJ
Maximum speed 13,000 rpm
Bearings Double ASBs
Motor PM motor
Flywheel A steel disk with a diameter of
200 mm, weight of 1.4 kg
Load A lamp of 12 V/10 W