Research on vector control system of beam pump used in CBM wells

Abstract

The beam pump unit is widely used in Coal-bed methane(CBM) wells for mining of CBM. In the past few years, the main electrical drive system applied in beam pump unit for CBM wells is electromagnetic speed motor. Aiming at drawbacks existed in electromagnetic speed system such as high energy consumption and low system efficiency, we propose a variable frequency speed system based on vector control technology for CBM wells. This paper analyzes and builds the mathematical model of the load torque of the beam pump and the mathematical model of AC drives control system of the beam pump using vector control technology. Based on the above analysis, we further set up the whole simulation model of the vector control system of beam pump for CBM wells. The simulation results show that the control system can automatically adjust the real-time dynamic torque motor current, in order to match the output torque of the motor with the load characteristics of the beam pump, and prove to having an excellent performance of speed control. The field experiment data verify that compared with the electromagnetic speed system, the proposed control method using in CBM wells can definitely improve the system efficiency and reduce the energy consumption.