Research On Vector Control System Of Induction Motor Under Explosion-proof Environment

In some flammable and explosive environment,such as underground mine and chemical plant,it is required that motors can not generate dangerous factors such as electric spark,arc or high surface temperature.The common motor is easy to produce electric spark and high surface temperature during operation,so it is not suitable for flammable and explosive places.Therefore,the explosion-proof motor is widely used in flammable and explosive environment because of its good heat dissipation equipment and no electric spark in operation.The driving device used in the early stage is the DC motor,which is characterized by good starting performance.However,the DC motor is replaced by the explosion-proof AC motor because of its carbon brush,uneasy maintenance and easy ignition during operation.Explosion-proof AC motor,especially the squirrel cage asynchronous motor,because of its simple structure,easy manufacture,low cost,and reliable,durable,requires little maintenance,capable of operating in harsh environments such advantages have been widely used in electric power,coal,petrochemical and other industries.During the operation of asynchronous motor,the speed information can be obtained by using the speed measuring device.However,when the speed measuring device fails,the speed of the motor will be seriously disturbed and the flying car is caused,and there is a great danger of safety.Therefore,the method of speed estimation without speed sensor has been applied and developed.Based on the speed estimation method of speed sensorless,the speed estimation of the motor stator current and voltage is carried out under the explosion proof environment.The main research work is as follows:1.The original dynamic mathematical model of the explosion-proof asynchronous motor is analyzed,and the mathematical model of asynchronous motor in different coordinate systems after coordinate transformation is introduced.Vector control is applied to control the explosion-proof asynchronous motor.2.The vector control scheme of speed sensorless for explosion proof asynchronous motor is set up,and the feasibility of the scheme is verified by simulation.3.Aiming at the problem of low speed estimation and inaccuracy caused by signal interference and motor parameter inaccuracy,a modified speed adaptive law is proposed,and the reliability of the scheme is verified.4.A hardware experiment platform for speed sensorless vector control of asynchronous motor is designed and built.Experiments are carried out in different working conditions,and the results are analyzed.