Position Sensorless Control of Permanent Magnetic Bearingless Synchronous Motor Based on Grey Model

The bearingless motor, which hybridizes the advantage of torque and magnetic bearings control, is one of the research fields of high and superhigh speed motor. It has been attacted extensive interesting in demestic and abroad. Because of the advantage of high reliability, easy to manufacture, and simple structure, the permanent magnet bearingless synchronous motor is found to be applied successfully in many fields, for instance, the semiconductor and life science.Sensorless technology of permanent magnet bearingless synchronous motor has the advantages of high reliability, low cost, short shaft length and small system size; it is suitable for high speed and high power operation, which can improve the dynamic performance of the system. It is difficult to measure the rotor position when the permanent magnet bearingless synchronous motor works in high or super high speed. Then the rotor position sensorless technology can be applied to get the position information.

Until now, a lot of work has been done on the position sensorless technology; it is mainly concentrated on low speed. The main purpose of this dissertation is to study position sensorless technology.In this dissertation the principle of the permanent magnet bearingless synchronous motor was stated firstly, then given the mathematical model of permanent magnet bearingless synchronous motor and analyzes the rotor flux orientation vector control system accordingly. Based on the above points, the dissertation mainly studies on the grey model estimation and system identification estimation method. The above two mathematical models are used to study on the principle of position estimation. The two sensorless control strategies both have the abilities to implemente the sensorless control, one is permanent magnetic bearingless synchronous motor based on grey model using analytic method and the other is permanent magnetic bearingless synchronous motor based grey model using identification method.

However, both strategies are dependent on motor parameters. In the mean while the motor temperature and the magnetic saturation have an impact on the control quality online parameter identification can be a good solution to this problem. In this paper,the initial position of rotor can be obtained by detecting the current change rate of winding coil which is connected to DC pulse when the stator core to reach saturation and the stator windings inductance decreases. Detection of the initial rotor position based on the using of the grey model identification method combined with parameter identification of the establishment of permanent magnet synchronous motor without bearing parameter identification online Sensorless control strategy. Then the principle is validated by the simulation in different speeds. The dissertations also modify these two methods to solve the problems during the simulation. After the simulation, the application of the position sensorless technology in the vector control of the permanent magnetic bearingless synchronous motor is coming true.According to the strategy of the position sensorless control proposed in this dissertation, the double DSP sensorless control system of permanent magnetic bearingless synchronous motor is designed which use DSP (TMS320LF2407A) as main control chip and use TMS320VC33 as assistant control chip.

Tags: neodymium magnets Permanent-Magnet£¬Synchronous-Motor Smco magnets