Investigation On All Digital Controll System Of Brushless DC Motor For Beam-pumping Unit

The Project is devoted to investigate the control methods of Brushless DC Motor(BLDCM) applied on Beam-Pumping Unit, and manufacture the correspondingcontroller.With the development of electronics and integral control technology, theelectronic devices have high performances and lower production costs. This lets thehigh-tech electrical integration of the instrument-BLDCM, has a broad prospects. Ithas a high power density, a high torque density, high starting torque, a high efficiencythat is larger than90%, and outstanding torque characteristics of medium and lowspeed. So BLDCM is fit for driving Beam-Pumping Unit and becomes the object ofthe investigation.The operation of Beam-Pumping Unit is a periodic process. In one stroke, withthe horse head rises/falls, the motor works in power-driven/electric-generative state.In former half stroke, the motor drives the Beam-Pumping Unit and consumeselectricity, the horse head goes up; in latter half stroke, the gravity pulls the horsehead down, so the motor is driven by Beam-Pumping Unit, generates braking torqueand electricity which is sent back to the grid.According to the operation principal of the Beam-Pumping Unit, a BLDCMspeed regulator with XC164as the core is designed. The system adopts twoclosed-loops (outer speed, inner current) with PI control strategy. The controllergenerates PWM wave to control the IGBTs in the3-phase full-bridge inverter, thusregulates the driving toque and the braking torque.Before produce the hardware, a complete BLDCM system model is constructedunder MATLAB/Simulink. The parameters are set close to the actual workingsituation. The simulation results prove the effectiveness and the speed-regulativeprecision of the controller.Both the results of testing the actual controller on bench and in field show thatthe system meets the design requirements, has excellent dynamic and static responses and steady torque output. The born of the control system promotes the BLDCMapplication in oil extraction field, and provides references to other motor controlsystems.