Research On Speed Estimation And Parameter Identification Of Asynchronous Motor

The proposed vector control system for asynchronous motors provides new ideas for highperformance AC control systems.In the motor speed control system,adding speed sensors will bring the defects of increased cost and difficulty in maintenance,and speed sensorless speed estimation can effectively avoid these deficiencies.In addition,the vector control equation of state contains the relevant parameters of the motor stator and rotor,these parameters in the operation of the motor makes the magnetic field vector orientation is not accurate,the AC speed regulation performance becomes worse,so it is necessary to identify the motor related parameters.Therefore,this paper does research on speed sensorless speed estimation and motor parameter identification of asynchronous motor.The main work of this paper is as follows:1.Speed sensorless speed estimation in asynchronous motor speed control.Firstly,the speed estimation model based on the model reference adaptive method is introduced in d etail.By analyzing the influence of the stator resistance of the motor on its identification at low speed operation,and the DC deviation caused by the pure integral link of the voltage reference model,a The speed estimation method using the motor itself as a reference model is modeled by Matlab/Simulink.The results show that this method effectively reduces the speed estimation error when the motor runs at low speed.2.Introduces the offline parameter identification method.Due to the limitations of traditional offline identification of noload and lockedrotor testing requirements for motor unloading equipment and installation equipment,this paper presents a static identification scheme by injecting different forms into the motor.The electrical signal,using the simplified Ttype equivalent circuit,can be used to calculate parameters such as stator and rotor resistance,stator leakage inductance,and mutual inductance of the motor.The motor parameters obtained through offline parameter identification ca n be used as initial values for online parameter identification.3.The method of online parameter identification of rotor time constant is introduced.The influence of rotor time constant change on the dynamic and static performance of the motor is analyzed.The model reference adaptive rotor time constant identification method based on flux linkage observer is introduced.The accuracy of the identification during operation is good,but it is affected by the change of stator resistance during low speed operation.Therefore,a rotor time constant identification method without stator resistance is proposed.By simulation and comparison,the identification of rotor time constants at low speed is basically determined by the disturbance of stator resistance.There is no effect on it.