Study On Sensorless Control Of PMSM Based On The Theory Of Extended Kalman Filter

With the widely use of permanent-magnet synchronous motor in many fields, the study on the permanent-magnet synchronous motor, a kind of inevitable development trend, has real meaning and value.Permanent-magnet synchronous motor (PMSM)is attractive for high performance drive systems because of its high efficiency and suitability for wide speed ranges of constant power operation. Mechanical sensors , limit the low speed operation of the machine, and is sensitive to the estimation of parameters, such as stator inductance and resistance.The demand of high performance and reliable drive system now pushes research toward the elimination of mechanical sensors. Recently, sensorless position control of motor is a challenge. There have been numerous publications on methods to eliminate the position sensor on motorsin the last several years.Based on the theory of nonlinear estimation, we researched on the sensorless control of PMSM. The thesis illustrates the principle of the (EKF) and it's application in the system, establishes the simulation model of the vector control system of PMSM based on the EKF and successfully realizes the application of the speedless sensor in motor control. Firstly, based on the mathematic model of permanent-magnet synchronous motor, the PMSM vector control system is built. Secondly, the Extended Kalman Filter is designed for the on-line estimation of the speed and rotor position by only using measurements of the motor voltages and currents. And then, with matlab7.0 software, the reasonability and validity of the EKF programmer in the motor control have been testified by the simulation results, which show the effectiveness of the system and the methods. At last, the improved method is proposed according to the decination of the results of the simulation.