Speed Sensorless Control Of Induction Motor Based On Sliding-mode MRAS

With the rapid development of speed sensorless control technology,the use of speed sensorless algorithm to obtain the speed,not only reduces the cost but also reduces the size of the motor,and improves the reliability of the system.Traditional speed sensorless control has the problem of inaccurate speed estimation in the low-speed zone.In high-precision applications such as engraving machines and robotic arms,the requirements for the accuracy of speed identification at low speeds are getting higher and higher,so speed sensorless control in low-speed areas has always been a research difficulty and hot spot.The speed sensorless control technology of Induction motors is studied.Firstly,it introduces and discusses the development status of the current widely used speed sensorless algorithms.Secondly,it discusses the principles,similarities and differences,and the scope of application of the three model referenced adaptive system(MRAS)speed estimation algorithms.Analysis.The method based on the rotor flux model has the advantages of high stability and reliability,strong anti-interference ability,and stable operation in the medium and high speed areas,but also has the problems of unsatisfactory speed estimation at low speeds and poor dynamic performance and robustness.This paper proposes an Induction motor speed identification algorithm based on sliding-mode MRAS,in which the adaptive sliding mode observer has the advantages of strong robustness and good dynamic performance,so it is improved by introducing the adaptive sliding mode observer adjustable model.The adaptive gain is added to the adjustable model.The output can be compensated according to the operating state of the system in real time,providing more accurate rotor flux observation,and the speed adaptive law is redesigned according to the Lyapunov stability theory.The accuracy of speed estimation and parameter robustness at low speed are improved.Through simulation and experimental research,the proposed method for estimating the speed of induction motor based on sliding-mode MRAS is verified.Compared with traditional methods,the dynamic performance is better,and the accuracy of speed estimation and the robustness of the system are also improved.