RESEARCH ON CONTROL OF FLYWHEEL SUSPENDED BY ACTIVE MAGNETIC BEARING SYSTEM WITH SIGNIFICANT GYROSCOPIC EFFECTS

Traditional PID controllers are no longer suitable for magnetic-bearing-supported high-speed flywheels with significant gyroscopic effects. Because gyroscopic effects greatly influence the stability of the flywheel rotor, especially at high rotational speeds. Velocity cross feedback and displacement cross feedback are used to overcome harmful effects of nutation and precession modes, and stabilize the rotor at high rotational speeds. Theoretical analysis is given to show their effects. A control platform based on RTLinux and a PC is built to control the active magnetic bearing (AMB) system, and relevant results are reported. Using velocity cross feedback and displacement cross feedback in a closed loop control system, the flywheel successfully runs at over 20 000 r/min.     

Preparation and characterization of novel porous metal/ceramic catalytic membrane materials

In order to obtain improved separation or catalytic activity, we propose a method to modify the surface of porous ceramic membranes by modifying the surface of sol particles. The key technical difficulty of this method is how to get appropriate ligands which can make metal ions adsorb on sol particles in the appropriate pH range in which the sol maintains its dynamic stability. Pd/γ-A1₂O₃ catalytic membrane materials with mesopore and a narrow pore size distribution were prepared by this method. Other kinds of metal/ceramic catalytic membrane materials such as Ni/γ-Al₂O₃, Pt/γ-Al₂O₃ can also be obtained by the same method.