Research On Speed Sensorless Vector Control Of Asynchronous Motor

With the development of electronics, microelectronic technology and moderncontrol theory, many kinds of electric drive system are researched and developed bymore and more domestic and foreign scholars. But because of the existence of thespeed sensor such as rotating coder, the installation of speed sensor is quitetroublesome and the demand of the installation is quit high. The scale and amount ofinduction motor vector control system with speed sensor is limited by thesedisadvantages. Speed sensor-less vector control system can solve the problemsmentioned above and reduce the cost of the system, which is meaningful both toimprove the reliability and adaptability of the AC drive system and to expand the ACdrive system’s application range. The study target of this thesis is to realizespeed-sensor-less vector control system of asynchronous motor. The study focuseson control method and estimation of rotor speed and flux of asynchronous motor.Firstly, progress of control strategies of alternating current motor andspeed-sensor-less vector control technology in recent years is summarized, and theadvantages and disadvantages of different strategies are enumerated and compared.Then the principles of vector control coordinate conversation and space vectorcontrol system based on model reference adaptive system (MRAS) is discussed.Based on the previous research, According to the structure of vector control systemwhich has speed sensor, a novel scheme of speed sensor-less field oriented vectorcontrol system based on MRAS (Model Reference Adaptive System) proposed. Theprogram Using voltage space vector pulse width modulation (SVPWM) controltechnology and field-oriented control (FOC) algorithm, in accordance with theprinciple of MRAS, which is use to estimate the value of speed for vector control.Based on these, the simulation of speed-sensor less vector control system with modelreference adaptive system is realized in MATLAB/SIMULINK, and the SIMULINKresults are discussed. The simulation results of established model show that theMRAS-based field-oriented control system has good static and dynamic performance,meanwhile, it is authenticated SVPWM control strategy is superior.Finally, this paper summaries in detail, the future research direction and contenthas made analysis and outlook.