Research On Speed Sensor-less Control System Of Asynchronous Motor Under Explosion Proof Environment

In the harsh environment with serious dust pollution,such as mines,mines and chemical plants,the coder in the speed measuring device of motor encoder is prone to friction with a large amount of dust in the air,resulting in sparks,resulting in dust explosion and even fire risk in the motor control system.The motor explosion-proof devices used in coal mines and chemical enterprises may also have some aging problems and design hidden troubles,so the existence of speed sensors will further reduce the explosion-proof safety performance of the motor,which will bring huge losses to property and life safety.Speed sensor-less control can overcome the hidden dangers of fire and dust explosion caused by speed sensor failure.It is of great significance to study speed sensor-less technology to improve the safety performance of motor control system.This paper takes the asynchronous motor in explosion-proof environment as the research object,and studies the control and safety of asynchronous motor in explosion-proof environment.The main contents of this paper are as follows:1.The dynamic mathematical model and vector control principle of asynchronous motor are analyzed.According to the dynamic model,the vector control system of asynchronous motor based on feed-forward decoupling is established.2.This paper analyzes the method of model reference adaptive speed identification,analyzes the reason of instability in low speed state,and puts forward the low speed identification control strategy of improved reference model(voltage model),which is verified by simulation.3.Starting from the mathematical model of the full order observer of asynchronous motor,the structure of the adaptive law and the feedback gain matrix of the full order observer is studied in detail.The stability of the low speed regeneration mode of asynchronous motor is analyzed by its transfer function.4.In view of the instability of asynchronous motor in low speed regeneration mode,the simplified gain matrix design criteria and weighted adaptive law are derived to ensure the low speed stability of asynchronous motor.The simulation results of traditional observer and improved full order observer show that the algorithm is feasible.5.The hardware platform of the speed sensor-less vector control system of asynchronous motor is designed,and relevant experiments are carried out using the experimental platform to verify the effectiveness of the above control strategy.