Research Of Hybrid Permanent Magnet Biased Magnetic Bearing Structure And Control System

Magnetic bearing is using magnetic force to the rotor suspended in the air, so that the rotor and stator can not make mechanical contact. As a kind of magnetic bearing, Permanent magnet biased magnetic bearings has been competing to research by national scholars and experts. Compared with the active magnetic bearing, permanent magnet flux replace the electrical excitation flux as the bias flux, reducing the control winding current, reducing the area of power devices and cooling, reducing the loss and improving efficiency.In this thesis, a structure of permanent magnet biased magnetic bearing is introduced. Then Introducing the working principle of the model, deriving the equivalent circuit of the entire bearing and calculating the electromagnetic parameters of the magnetic circuit. According to the results of electromagnetic parameters of permanent magnet biased magnetic bearings design specific size, calculate and select every part of the parameters and the materials by giving some specific prototype model. By deriving a mathematical model of Permanent magnet biased magnetic bearings, according to equivalent circuit theory, using Matlab/Simulink software to build simulation model of magnetic bearings, the simulation data is consistent with the calculated data to verify the correctness of the simulation model. With this model, the coupling between the electromagnetic force is analyzed to lay the foundation for the controller design. Eddy current sensor is used to measure the position of rotor. The thesis will introduce the principle of eddy current sensors, design the structure diagram which detected by eddy current sensor for the position of rotor, and explain how it works and the installation process. At last it is shown that detection circuit, detected by the eddy current sensor for rotor position.Full-bridge circuit is used as the basic form of control winding and power amplifier with hybrid magnetic bearings is used as power actuator of Permanent magnetic bearing paranoia power permanent magnet. The simulation results of Multisim10.0 software with the performance of hybrid power amplifier show that the hybrid power amplifier has good following characteristics on the step and sinusoidal signals, which meet the requirements of the power amplifier of magnetic bearings.