Optimization Design And Development Of Rectifying Device In Oil Well Group Control System

Oil well group control system is more and more widely used in the oil production industry.There are many problems in the application of various frequency conversion control devices to achieve production increase and energy saving.For group control system,the working condition of its load is constantly changing,which puts forward higher requirements for the development of control device.In the early stage,the research group developed IGBT four quadrant PWM rectifier which can realize energy mutual feeding and energy saving,so that the inverted power generation on DC bus can be reused by other motors.However,there are three problems in the field operation:(1)The DC side voltage is too high occasionally at the moment of start-up.(2)When the balance degree of the beam decreases,the peak valley difference of the periodic load of the up and down stroke motor increases,and the load fluctuation of the rectifier device intensifies,resulting in the DC side voltage fluctuation occasionally exceeding the allowable range.(3)The transient voltage fluctuation of up stroke and down stroke is large.Therefore,the focus of this paper is to study and analyze the variation law of DC side voltage with load fluctuation of oil well PWM rectifier under the classical PI control,and improve the control method and technology for the existing problems,and apply the research results to the embedded rectifier measurement and control system.Firstly,the working principle of oil well PWM rectifier is analyzed and its mathematical model is established;On this basis,the control method of rectifier is analyzed.In order to improve the ability of PWM rectifier to cope with variable load,the feedback linearization control method is adopted in this paper.Based on affine nonlinear system and differential geometry theory,the system model of PWM rectifier under input-output feedback linearization control is established,and the feedback coefficient is determined by the placement of system poles.Secondly,the simulation model based on double closed-loop PI control and feedback linearization control is established in Matlab Simulink,and the three-phase PWM control signal is generated by space voltage vector modulation(SVPWM).The simulation results of the two control methods are compared and analyzed to demonstrate the effectiveness of the control method.Finally,the hardware experimental platform based on TMS320F28335 is constructed to design the data acquisition and processing,DSP control system,voltage and current sampling conditioning circuit and driving circuit.The program control code is written,and the experimental test and performance analysis are carried out to simulate the oil well load condition.The results show that the control method used in this paper can effectively improve the system response time,system response overshoot,system load carrying capacity and other indicators of the rectifier device in the oil well group control system,compared with the traditional PI control rectifier device used in the early stage of the research group,in the face of various load changes in oil well production,so it significantly improves the stability of the DC side voltage,The performance of the device is optimized.