Research On Position-Sensorless Control System Of Induction Motor Based On Full-Order Flux Observer

Induction motors are widely used in various fields of national production due to their unique advantages such as simple structure,durability,and low cost.Due to its excellent performance in steady-state accuracy and dynamic performance,vector control strategy has become the mainstream control method for induction motor speed control systems.As the key to achieving high dynamic performance in a speed control system,the motor speed is usually obtained through the installation of position sensors.However,this can lead to problems such as increased system volume,reduced reliability,and limited application scenarios,which has driven the rapid development of speed sensorless control technology for induction motors.This article aims to improve the performance of induction motor sensorless vector control system,and studies and improves the dynamic decoupling and speed identification of vector control.Firstly,the mathematical model of induction motor is established,the basic principle of rotor field oriented vector control of induction motor is expounded,the key technologies of rotor flux observation and field orientation are analyzed,and the simulation model of double closed loop vector control of induction motor is built to verify the effectiveness.Secondly,in order to realize the dynamic decoupling of vector control of induction motor,this thesis introduces the feedback linearization control theory.By redefining the state quantity,the dynamic decoupling of electromagnetic torque and rotor flux linkage of induction motor is realized by using coordinate change.Considering the influence of motor parameter change and measurement error on feedback linearization,model error compensation control is added.In order to further improve the dynamic performance and anti-disturbance performance of the control system,sliding mode controllers are designed for rotor flux and motor speed respectively,and the feasibility of the algorithm is verified by simulation.Then,in order to solve the instability of the speed control system based on the fullorder flux observer for speed identification at low speed,this thesis establishes the mathematical model of the full-order flux observer,deduces the speed adaptive law according to the Lyapunov stability theory,analyzes the reasons for the instability of the speed identification system based on the traditional speed adaptive law at low speed,and gives the constraint range of the feedback matrix selection.While ensuring the stability of the low-speed power generation operation,a suitable feedback gain matrix is designed to improve the robustness of the estimated rotor flux linkage to the change of motor parameters,and the system stability and parameter sensitivity are verified for the improved feedback matrix.Finally,through the establishment of an induction motor experimental platform to compare and verify various algorithms,the results show the effectiveness of the improved algorithm.