Study On Special Screw Pump Position-Sensorless Brushless DC Motor Controller In Oilfield

Thesis first introduces briefly the application of screw pump in oilfield, clarifying the advantages of brushless DC motor as screw pump driving and predicting its application prospects.With the continuous development of control theory and the appearing of new power electronic devices and new permanent magnetism materials, brushless DC motor has found more and more application in various areas of national economy. In this process, the advantages of position-sensorless control detection method have become increasingly obvious.Through the analysis of the structure of brushless DC motor and its basic working mechanism, centering on the core problem of the technology of brushless DC motor position-sensorless control, namely, how to get indirect gain reliable rotor position signals by means of reasonable design of hardware and reasonable programming of software, discussing in detail the control system of position-sensorless brushless DC motor.First, we make an in-depth analysis of the harmonic potential detection principle. Second, aiming at the phenomenon of low speed feedback signals when the motor is static or at low speed, we put forward a 3-sectional startup method based on the 3-winding pre-location as a prerequisite, and then make a modeling simulation of the control system scheme, using MATLAB7.1/Simulink to ensure its feasibility, providing a basis for the design of the system's hardware and software, designing the system hardware circuits with TMS320F2812 DSP as the core, and compiling the software flow chart.Finally, through the experimental platform, we make related experiments on the whole motor control system, giving the experimental results and experimental analysis, and proving that the brushless DC motor for position-sensorless controller developed in this paper is running well.