Research On Frequency Conversion Speed Control Method Of Conventional Pumping System

The conventional oil pumping system has the advantages of simple mechanical structure,convenient maintenance and long service life.It is widely used in oilfield exploitation,but there are generally problems of low pumping efficiency,large motor energy consumption and low degree of automation.As the oil supply capacity of the oil field declines,the disadvantages of the above conventional pumping units are highlighted.The frequency conversion speed regulation technology is used to perform energy-saving transformation on the pumping unit,adjust the frequency of the pumping unit,and change the up and down stroke speed of the pumping unit according to actual needs to make the pumping The system is running in the best working state.Through the analysis of the working principle of the conventional pumping system,the kinematics analysis of the beam pumping unit is carried out,and the MATLAB software is used for modeling and simulation;on the basis of the kinematics theory analysis,the dynamics of the pumping system is analyzed.The oil pumping system is simplified into an equivalent mechanical model.According to the working principle of the three-phase asynchronous motor and the working principle of the frequency converter,the frequency conversion speed regulation simulation model of the oil pumping system is established.The frequency converter and the motor are simplified into a transfer function,and the PID algorithm is used to simulate the variable frequency speed control of the pumping system,and the simulation is performed using MATLAB / Simulink software.Through the simulation of vector control,direct torque control,variable frequency conversion control and slip control algorithm,and analyze the simulation results.According to the four frequency conversion speed control methods,the three-phase asynchronous motor is controlled at zero load,and the motor speed curve and torque curve are compared and analyzed.Under the four frequency conversion speed control methods,the input of the motor is in accordance with the periodic alternating load of the pumping system.The simulation curves of the motor speed and electromagnetic torque under the four control methods are compared and analyzed.