地面驱动螺杆泵转速自动控制技术研究

发布时间：2019-07-10 13:56

【摘要】：地面驱动螺杆泵采油举升技术以其结构简单、流量和压力稳定、适应性强等优点,在稠油井和含砂、含气比例高的油井开采中得到了日益广泛的应用。以地面驱动螺杆泵采油举升过程中的转速控制为切入点,详细研究了沉没度对转速控制的影响,阐述了地面驱动螺杆泵的软启动和软停车的控制理论和方法,确定了以直接转矩控制方式为异步电机变频控制系统的策略,并对传统的PI转速控制器进行了模糊改进,对仿真结果进行了优劣对比。论文首先阐述了沉没度对油井泵效、系统效率、检泵率的影响,在利用加权平均函数分析最佳沉没度的基础上,根据油井的流入与流出供排平衡关系,实时跟踪匹配油井的供液能力,建立起地面驱动螺杆泵的转速控制模型,根据不同的动液面选择合理的转速,提高地面驱动螺杆泵的采油效率。接着详细介绍了地面驱动螺杆泵软启动和软停车的控制理论和方法,分析了软启动的上升时间,以及软启动过程中所需的启动转矩以及启动电流,选择S形的升速方式。根据异步电机停车过程中的机械特性选择合适的降速时间和S形的降速方式。分析了螺杆泵井停机时的反扭矩的组成,确定出了软停车过程中所需的制动扭矩,并建立了变频调速系统的输出频率变化与制动转矩的关系。最后,阐述了异步电机的直接转矩控制技术的基本原理和系统结构组成。在Matlab/simulink环境下建立了直接转矩控制系统的仿真模型,针对传统PI速度控制器对突加负载或速度变化时,转速和转矩响应慢、抗干扰能力差的问题,引入模糊PI速度控制器,选择合理的参数整定。仿真实验结果表明:改进后基于模糊速度控制器的直接转矩控制系统比传统基于PI速度控制器的直接转矩控制系统的超调量更小,响应速度更快,调速系统的动态响应得到明显的提高。
文内图片：

图片说明：沉没度对检泵率影响
[Abstract]:Surface driven screw pump lifting technology has been widely used in heavy oil wells, sand bearing wells and oil wells with high gas content because of its simple structure, stable flow rate and pressure, strong adaptability and so on. Based on the speed control of ground driven screw pump in the process of oil production lifting, the influence of subsidence degree on speed control is studied in detail, the control theory and method of soft start and soft shutdown of ground driven screw pump are expounded, the strategy of using direct torque control as induction motor frequency conversion control system is determined, the traditional PI speed controller is fuzzy improved, and the simulation results are compared. Firstly, this paper expounds the influence of subsidence degree on oil well pump efficiency, system efficiency and pump detection rate. on the basis of analyzing the optimal submergence degree by using weighted average function, according to the balance relationship between inflow and outflow of oil well, tracking and matching the liquid supply capacity of oil well in real time, the speed control model of surface driven screw pump is established, and the reasonable rotational speed is selected according to different dynamic liquid levels to improve the oil production efficiency of surface driven screw pump. Then the control theory and method of soft start and soft shutdown of ground driven screw pump are introduced in detail, and the rising time of soft start, the starting torque and starting current needed in the process of soft start are analyzed, and the S shape speed raising mode is selected. According to the mechanical characteristics of asynchronous motor in the process of stopping, the appropriate speed reduction time and S-shaped speed reduction mode are selected. The composition of the reverse torque when the screw pump well is shut down is analyzed, the braking torque needed in the process of soft shutdown is determined, and the relationship between the output frequency change of the variable frequency speed regulation system and the braking torque is established. Finally, the basic principle and system structure of direct torque control (DTC) technology of asynchronous motor are described. The simulation model of direct torque control system is established in Matlab/simulink environment. Aiming at the problem of slow response of speed and torque and poor anti-interference ability of traditional PI speed controller to sudden load or speed change, fuzzy PI speed controller is introduced and reasonable parameter setting is selected. The simulation results show that the overshoot of the improved direct torque control system based on fuzzy speed controller is smaller than that of the traditional direct torque control system based on PI speed controller, the response speed is faster, and the dynamic response of the speed regulation system is obviously improved.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE355.5;TP273

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