Control And Simulation Of The Direct-Drive Pumping Unit Simulation System

As the most widely used equipment, the beam pumping unit plays a significant role in the artificial oil equipments. But it has some shortcomings, such as a long transmission chain, large power consumption and low efficiency etc. For pumping unit on oil field, energy saving and lower production costs become the focus of attention.A system scheme of direct-drive pumping unit is presented in this paper, by the low-speed outer rotor brushless DC motor instead of the traditional high-speed induction motor, to solve the problems of the conventional beam pumping unit base on the analysis of the feature and application of brushless DC motor.Identified the system structure of the direct-drive pumping unit in this paper, and explained how it works; analyzed the motion rule and the change of suspension center load and balance principle; Analyzed and compared the brushless DC motor direct-drive pumping unit system’s efficiency with the traditional beam-pumping unit system’s, and proved that the former better than the latter; calculated the braking energy and braking resistance; established the math model of brushless DC motor, and built the Matlab/Simulink simulation model of its control system according to the math model, and tested the control system; designed and welded the board of the control system based on the brushless DC motor control ASIC, including the control circuit, drive circuit, inverter circuit, the steering control circuit and the auxiliary circuit, and tested the control system board, to verify the feasibility of the system program.Analysis shows that, the outer rotor brushless DC motor direct-drive pumping unit removed the reducer and the four-bar linkage, reduced the transmission chain greatly, and overcome the shortcoming such as poor control and low efficiency.