Design And Implementation Of Energy-saving Control System For Vertical Lathe

Large vertical lathe calls for great improvements since the fact that it cannot meet the requirements of modern processing technology,due to the intensive tasks and inconsistently,its backward operation mode.Taking the C523 lathe as the object,the electric control system is designed based on PLC,and closed-loop control system is formed by adding frequency converter,frequency converter motor,spindle encoder and PID regulation.Vector control frequency conversion speed regulation system is designed.The system regulates the speed of three-phase asynchronous motor,so as to control the motor to achieve the function of high power low speed and energy saving.Nowadays,AC speed regulation system has been widely used in various fields of life,and also in industry,agriculture,military industry.Common frequency converter drivers are AC-AC system and AC-DC-AC system.The power supply range of large vertical lathe varies from 350 V to 430V.In addition,the three-phase asynchronous motor frequency conversion driver for this purpose also needs higher requirements for performance,speed range and waveform quality.Now the research status of domestic and foreign converters is analyzed,and the data are integrated.It is found that the vector control variable voltage variable frequency speed regulation method can control the speed of three-phase asynchronous motor very well,and the speed regulation performance and the ability with load are strong.When studying the control method of vector controlled three-phase asynchronous motor,the theoretical basis and principle of vector control,the principle and method of coordinate transformation are briefly introduced.And the vector control scheme of induction motor oriented by rotor flux is selected.The specific idea is rotating.And coordinate system is built on the rotor flux,and the stator current vector is used to control the torque of induction motor by decoupling the three-phase current.This scheme can make the speed regulation performance of AC motor comparable to that of DC motor.In order to improve the waveform quality and further improve the system performance,the double closed-loop induction motor vector control system has good dynamic performance,stable static performance.And it can meet the requirements of continuous frequency regulation and reduce waveform distortion.In this thesis,the AC vector control system of the vertical lathe is simulated and analyzed in MATLAB/SIMULINK.The DC speed regulation system is simulated and analyzed in MATLAB/SIMULINK.By comparing the simulation results of AC vector control system and DC speed control system of vertical lathe,it is concluded that the speed of DC speed control system is overshoot,while the speed of AC vector control system of vertical lathe can be adjusted steadily from zero,with little fluctuation.Because the speed regulation method is simple and reliable,the cutting ability and efficiency are improved,the operating speed of the worktable is improved,the system is free of maintenance,and the electric energy and maintenance cost are greatly saved.