Research On Parameter Identification Of Induction Motor Based On The Sliding Mode Observer

The introduction of the vector control and direct torque control strategy has greatly improved the speed control performance of the induction motor,so that it can reach the level of the speed control performance of the DC motor.The advantages of induction motors in terms of cost,reliability and power density make the induction speed control system the mainstream method in the field of electric drive.However,for induction motor control systems,especially vector control systems,the accuracy of the parameters directly determines the operating performance.Although the motor's nominal parameters can be obtained through the factory experiment or the auto-tuning process,the motor parameters usually deviate from their nominal values due to factors such as temperature,skin effect,and magnetic saturation during operation.For widely used indirect field oriented vector control systems,the key parameters that determine their performance are the rotor time constant(or the rotor resistance)and magnetizing inductance parameters,and they change with the changes of motor temperature or magnetic saturation.In particular,changes in the rotor time constant with temperature are difficult to correct by means of look up table or curve fitting.For this reason,the online correction of the parameters becomes the key to the improvement of motor control performance,and it is also a hot issue studied by academic circles in recent years.In this paper,the sliding mode observer is designed to realize the online identification of the rotor resistance,the rotor time constant,and magnetizing inductance of indirect field oriented induction motors,which improves the steady state and dynamic performance of the vector control system.The main work of this paper is as follows:1,Based on the mathematical model of induction motor,the indirect vector control system of induction motor is designed,and the influence of rotor time constant deviation is analyzed and discussed;2,In order to solve the problem of the influence of the resistance on the rotor time constant,a double compound manifolds sliding mode observer is proposed.Through the discussion of its construction process and physical mechanism,the nature of the compound manifolds is clearly revealed.The defects of the single compound manifolds sliding mode observer can be exposed,and the proposal of dual compound manifolds sliding mode observer can be naturally presented,thus perfecting the design theory of the compound manifolds sliding mode observer;3,The designed double compound manifolds sliding mode observer can accurately realize the online identification of the rotor resistance,and has strong robustness for load and parameters.Which are further proved by simulation analysis;4,Aiming at the question of the calculation of the current command value requires the use of a magnetizing inductance in electric vehicle applicationslarge and changes in inductance parameters In the case of wide weakening magnetic speed range of the new energy vehicle electric drive and so on.This paper further designs a double compound manifolds sliding mode observer that can simultaneously identify the rotor resistance,the rotor time constant,and magnetizing inductance parameter online,based on the structural mechanism of aforementioned dual compound manifolds sliding mode observer.5,A lOkW induction motor vector control system simulation model and experiment platform are built.,the analysis and design of this paper are validated through simulations and experiments.