Study On A Seperated Magnetic Circuit Magnetic Bearing System And Its Related Problems

The principle of a magnetic bearing is that the rotor is suspended by dynamic electromagnetic force, to realize no touch support between the stator and the rotor. Because of these advantages such as no wearing, without lubrication and suitable for operating at high speed, magnetic bearings are widely applied in high speed and ultraclean situations, for example, in high speed main axis, flywheel in satellite, etc. In hybrid magnetic bearings permanent magnet is used to produce bias magnetic field instead of electromagnetic field, which reduces the electric loss and also mechanical volume of the bearing, and becomes an important development aspect. Therefore, the study on theses magnetic bearings processes important meanings to their engineering applications.The working principle and development of the magnetic bearing are introduced in this paper first. On the basis of previous work, a novel structure magnetic bearing is designed here. According to the structure and working principle of the magnetic bearing, the mathematical model is derived, which proves the principle of the magnetic bearing is correct theoretically.The magnetic field of the magnetic bearing is generally computed and analyzed with three dimensional FEM tool Flux3D. Computation results of static characteristics certify that the magnetic coupling between X and Y dimensions is far smaller than that of traditional hybrid magnetic bearings.On the basis of mathematic model of the magnetic bearing, the simulation model of the whole magnetic bearing system is constructed. PID control method is adopted in the process of simulation. Finally the simulation results are deeply analyzed.According to the demand of the whole magnetic bearing, a differential transformer type transducer is also designed here, which can be installed together with the magnetic bearing. The experiment of the displacement sensor is carried out.