Research On Speed Sensorless Vector Control Of AC Motor Based On Fuzzy PI Control

AC Motor Speed Control is an important question in the AC drivesystem, the vector control technology achieves a decoupling between theexcitation component of the AC motor stator current and torquecomponent, which makes AC motor to be able to get a good dynamictorque response performance; Speed sensorless control eliminates theneed for physical installation of the speed sensor, simplifies the systemhardware structure, improves the reliability of the system, and reduces thecost through estimating speed of the motor on line. Therefore, thecombination of the speed sensorless control and the vector controltechnology has the high practicality and economy, becomes a hot researchat home and abroad in recent years.In this paper, the speed sensorless vector control meth in whichmotor speed is estimated using MRAS was studied and improved, myresearch work is mainly as follows:The dynamic mathematical model of AC asynchronous motor wasestablished and designed closed-loop with torque and flux through theprinciple of the rotor field oriented principle. For voltage type rotor fluxobserver of the pure integrator, easy to cause the problems of dc drift andinitial value error, focuses on the use of modified integrator of anadaptive orthogonal compensation, thus effectively improved theobservation accuracy of flux linkage and observation.The speed identification method based on the rotor field orientedwas researched and made theoretical analysis on the system stability.Because of the characteristics of nonlinear, variable parameter system andfuzzy adaptive PI control were adopted in the system, the response speedand robustness of the system was improved.Simulation results showed that the speed sensorless vector controlsystem had a better static and dynamic performance, which can track thevariation of the motor speed accurately, and had strong robustness andstability.The software programs of the speed sensorless vector system was designed based on TMS320F2812, and made detailed experimentalverification in hardware experimental platform, experimental resultsshow that the designed system with good performance.