Research On Speed Sensorless Optimization Of Induction Motor Based On Adaptive Full-order Observer

Asynchronous motor speed sensorless vector control system is widely used in various fields because of its simple structure,low cost,low maintenance and use cost,able to adapt to harsh conditions and many other advantages.However,because there is no speed sensor feedback motor real-time speed,only through the vector control algorithm to real-time observation of speed.In many control methods,the most commonly used model reference adaptive method and full order observer method are introduced in this paper.However,there are some defects in the method of model reference adaptive method and the traditional full order observer method,based on the traditional full order observer method,this paper improves the stability of the adaptive full order observer at low speed by improving the speed adaptation law and the feedback matrix.The main contents of this paper are as follows:1.In this paper,the research status of vector control technology of induction motor without speed sensor is described,and the advantages and disadvantages of various control methods are introduced.2.The dynamic mathematical model of asynchronous motor in three coordinate systems is listed,and the expression of the transformation between the three coordinate systems is derived;the principle of vector control and the SVPWM control principle and the realization method are introduced in this paper.3.The basic principle,the state equation and the speed adaptive law of the model reference adaptive method are studied,and the defects of the model are analyzed;the full order observer is proposed,and the structure of the full order observer,the design of the feedback gain matrix and the derivation of the speed identification are introduced.4.Due to the instability of the traditional full order observer at low speed,the reasons of instability are analyzed,and three improvements are put forward:(1)On-line identification of stator resistance;(2)the improved speed adaptation law is obtained;(3)the design of the feedback gain matrix is reasonable.Then the improved adaptive full order observer is obtained.5.Compared with the traditional full order observer model and the improved adaptive full order observer model,the improved adaptive full order observer is proposed to improve the stability of the system at low speed;and the experiment was carried out on the 30KW asynchronous motor on the experiment platform,and the effectiveness of the improved measures was verified.