Research And Application Of Speed Sensorless Model For The Induction Motor

In terms of the speed-control systems,a closed-loop speed control can improve the performance of the system.So,it needs a sensor to measure speed to achieve the purpose of high-efficient speed control.However,the presence of speed-sensor brings many problems,such as poor reliability,installation difficulty and high maintenance costs.Nowadays,it has become a very hot topic to avoid the speed-sensor and estimate the speed with the known information.Because the main driving force of the motor drive system is the motor,therefore,how to improve the motor body to improve the performance of the engine speed control system has become the key to solve this kind of problem.This paper introduces several kinds of speed-estimation methods,analyzes their advantages and disadvantages,and in-depth studies the mathematical model of the induction motor.Then,this paper analyzes two kinds of common flux models,combine both of them and an improved hybrid flux linkage model is constructed by the concept of slip angle frequency,the model makes the system performs well in both low-speed and high-speed.According to the reasonable analysis,The reference model and the adjustable model are established by the current error output.The adaptive law of the adjustable system is derived by the Lyapunov stability theorem,and the stability of the system is further verified.Because of the great influence of the parameters of the system,parameters are identified in this paper to makes the system achieve the highest performance requirements.According to the theoretical analysis,this paper uses the MRAS method to estimate the speed,it avoids many impacts of the speed-sensor to the system.Simulation platform of control system is built in Matlab/Simulink simulation environment.Various operating conditions of the motor are simulated.Error is introduced in the system,and the parameters identification of the actual situation is simulated.The simulation results prove the feasibility of the scheme,and the system has some practical value in practical application.