Research On Sliding Mode Speed-sensorless And Simplified Predictive Torque Control For Induction Motor

Induction motors are usually used as motors.It has the advantages of simple structure,low cost,easy maintenance and reliable operation,so it has been favored by researchers.With the development of power electronics technology,research on induction motor control is also emerging.Model predictive control is a new control method with excellent dynamic and steady characteristics.The traditional motor control strategy needs speed sensor.The speed sensorless control method can simplify the hardware structure and reduce the cost and volume of hardware.Based on the above content,this paper studies the speed sensorless model predictive control technology of induction motor.The main research work of this paper is as follows:(1)The structure and working principle of induction motor are analyzed.The mathematical model of induction motor based on differential equation is deduced and given,which determines the theoretical basis of model predictive control technology and speed sensorless control technology.Besides,the theoretical basis of field oriented control,direct torque control and model predictive control is introduced for the comparative analysis.(2)The predictive equations of induction motor for model predictive control are discussed in detail,and the specific implementation method of traditional model predictive torque control is given.In view of the shortcomings of the traditional method of large amount of calculation,a new simplified model predictive control method is proposed.By introducing a new torque calculation scheme and a multi-step and multi-objective model predictive control strategy,the cost functions of torque and flux amplitude are separated.Compared with the traditional model predictive control method,the calculation burden is reduced and the influence of weight factor is avoided.Based on MATLAB/Simulink simulation environment,the simulation model of induction motor control system using model predictive control strategy is built,and the relevant simulation results are given to verify the feasibility of the design scheme.(3)The sliding mode observer system is introduced,and the observer equation of using the sliding mode observer to observe the speed of induction motor is derived theoretically.By introducing the sliding mode observer,the measured speed in the prediction model is replaced by the observed speed,and the speed sensorless control is realized,which avoids many inconveniences caused by the speed sensor.Based on the MATLAB/Simulink simulation environment,the simulation results of motor speed,torque,current and so on with the proposed observer and control method are given,and compared with the traditional field oriented control and direct torque control.The simulation and comparison results verify the effectiveness of the control method.(4)On the basis of the above theoretical research,the experimental platform of induction motor control system is built based on TMS320F28335,and the joint debugging of software and hardware is realized.The experiments of induction motor model predictive control system and speed sensorless model predictive control system based on sliding mode observer are carried out,which further verify the feasibility and effectiveness of the proposed algorithm.