Research On The Sensorless Vector Control Technique Of Permanent Magnet Synchronous Motors

Permanet magnet synchronous motors(PMSM) are receiving increased attention for drive applications because of superior power density and high efficiency. It is extensively used in the AC drives. Motion control of PMSM requires accurate position and velocity signals to realize field orientation. In conventional motion controls, optical encoders or electromagnetic resol-vers are used for this purpose However these additional sensors increase the cost of system and decrease the reliability, all this restrict the applied range of PMSM.With this background, The elimination of position and velocity sensors has been an attractive prospect. Sensorless control is fast becoming a requirement. At present, scholars in the world have advanced several detection methods,But most of these techniques only rely on the fundamental machine equations,which limits the low speed and zero soeed operation of the machine,and are sensitive to the machine parameters.The thesis takes embed PMSM as subject investigated and foucuses on the sensorless operation in the whole speed region,including zero speed.Firstly mathematical models in different coordinate system of PMSM are set up based on electromagnetism, and study the conversion between them.Based on these models,the vector control method theory are discussed and introduces the methods in common use.Secondly,considering the methods of flux linkage needing high accurate signals of position and velocity,the thesis advances the rotor position detectin method basing on adaptive flux linkage observer.The method regard PMSM as reference model.Use stator flux and stator current in tow still coordinates ystem as state variables to set up observer.Use the error of stator current to form adaptive laws.Based on this method,set up the simulation model of the vector control system of PMSM. The results indicates that the method is not sensitive to parameter's change, can have poison signal accurately.Thirdly,based on the saliency tracking idea,the high frequency vlotage signal injection was discussed in this thesis.The basic principles of rotor...