|Budget Amount *help
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 2002: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥4,600,000 (Direct Cost: ¥4,600,000)
Recently, saving energy effectively has become very important. Thus, energy-saving technology for surplus power is very important. A flywheel energy storage system is one of the valuable energy-saving technologies. The system is very simple and characterized by high energy saving compared with other energy storage systems. Also, high temperature superconductors with strong pinning force are useful for this application.
In this research, we propose a miniature flywheel energy storage system. HMBs with H-infinity control method are applied to the flywheel energy storage system. The dynamics of the energy storage system is discussed.
We have developed a prototype miniature flywheel energy storage system. The system consists of a rotor with a flywheel disk and a pair of HMBs. The rotor measures 270 mm in length and 24 mm in diameter with a flywheel disk (100 mm in diameter). The rotor mass with the flywheel is 1.2 kg, which is supported by the repulsive force between two permanent magnets (PMs). In our system, the two SMBs are more dominant than the two AMBs. This means that the AMBs assist the SMBs. In order to suppress the rotor vibration near the resonance rotation speed, H-infinity control is applied to the two-axis AMBs. Except near the resonance rotation speed, the SMBs mainly suppress the rotor vibration. The superconductors of the SMBs were field-cooled. Moreover, a nonlinear control method without bias corrents is applied to the AMBs. That is, in the rotor control, the two electromagnets facing each other along each axis aren't excited by the driving currents at the same time.
Furthermore, a flywheel system without control is studied. The system is almost equal to the system mentioned above. Also, improvement techniques for the bearing stiffness and damping of the superconducting bearings are studied. From this study, it is found that the flywheel system without control is useful for energy storage.