| With the gradual reduction of oil energy and the gradual enhancement of energy conservation awareness, the development trend of oil field exploitation is to improve the working efficiency of oil pumping unit and reduce the power loss, reasonable matching of oil pumping unit and driving motor is one of the effective measures to reduce the cost of oil field production. The switched reluctance motor (Switched Reluctance Motor,SRM) has the advantages of small starting current, large starting torque, high power factor, simple structure, easy speed regulation, etc., suitable for use as the driving motor of oil pumping machine, more and more used in oil field production.The SR motor drive system for the beam pumping unit is studied in this paper, the torque characteristics of the beam pumping unit and the electromagnetic characteristics, torque characteristics and control characteristics of the SR motor are introduced, a coupled model of the SR motor and the beam pumping unit is established, a method for detecting the load torque switching point of pumping unit without external sensor is proposed, the double closed loop control strategy of subsection PI parameters is established.The different subsection PI parameters and the power-logic mode are given when the pumping unit is in different torque zones, the output torque of SR motor can follow the load torque very well, to ensure the steady operation of pumping unit and to improve the efficiency of the system and energy saving effect.Finite element analysis software FEMM is used to analyze the electromagnetic field of the SR machine with the rated power of 11kW, rated voltage of 514V and rated speed of 750r/min, modeling and Simulation of oil pumping unit and SR motor coupling model using MATLAB/simulink software, simulation results show that SR motor drive system using the control strategy proposed in this paper can match the pumping unit load well, smaller starting current and motor speed stability at the command value, current can follow the torque change of pumping unit in real time, the work efficiency of pumping unit and the oil field production cost are reduced indirectly.Then the problem of vibration and noise reduction of SR motor is studied, studied radial force analysis and a DIFC control strategy is proposed to compensate the radial force of the adjacent windings which are in the inductance drop zone during the phase change,then the control strategy of DIFC is modeled and simulated by using Simulink software,simulation results verify the feasibility of the DIFC control strategy to suppress the vibration and noise of the SR motor.According to the system control strategy proposed in this paper, the hardware circuit design and software programming of the SR motor drive system are designed respectively, selecting SR motor prototype and CYJ3-2.1-13HF beam pumping unit as the experiment object. Experimental results show that the oil pumping unit can work stably with the subsection PI double closed loop control strategy which uesd braking power-logic, SR motor starting current is small and reflects a good speed response; by comparing the experimental data of the SR motor with the same power of the three phase induction motor can see that SR motor drive system has higher efficiency and significant energy saving effect. |
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