Design And Analysis Of Supercapacitor Energy Storage System For Conventional Pumping Units

At present,most of China's oil fields have been developed in the middle and late stages.The main mining method in China is mechanical oil extraction.Conventional beam pumping units are the most widely used mechanical oil extraction in major oil fields.Conventional beam pumping units are simple and practical in structure,strong in reliability and long in technical maturity.However,due to the limitation of their own structure,there are problems such as low overall efficiency of rod pumping system,power generation phenomenon of motor,poor balance effect,etc.The annual energy consumption is also considerable.According to the phenomenon of motor power generation,the traditional method is to use the thermal effect of braking resistor to consume this part of energy,which is not fully utilized.If energy is fed back to the power grid,harmonic pollution or low efficiency will occur.Based on this,this paper uses supercapacitor to recover this part of energy,and releases it when the pumping unit motor is running electrically to relieve the power grid pressure,so as to achieve the purpose of stabilizing the DC bus voltage of the frequency converter,saving energy and reducing consumption.Firstly,the operation principle of the pumping unit is analyzed,and the power generated by the motor when lowering the rod is calculated.The connection scheme between super capacitor and pumping unit is established,and the working principle of bidirectional DC/DC converter is analyzed and the topological structure is selected.According to the access scheme,the overall control strategy of the energy storage system is designed,the charging and discharging modes of the super capacitor are analyzed,and the charging and discharging modes suitable for the working conditions are selected.Finally,parameters matching,selection and structural design of super capacitor are carried out.Energy storage system has its own characteristics of non-linearity and large input and output disturbances,and the general PID control method can no longer meet the demand.Therefore,this paper adopts adaptive control method to control bidirectional DC/DC converter,which is robust to model deviation and external interference.Based on Matlab/Simulink platform,the control strategy and control algorithm are simulated and verified.In the end,this paper carries out field experiments to verify the overall scheme,and goes to the field to carry out experiments after the previous experimental design and device selection.After processing the experimental data,the experimental results of conventional pumping unit supercapacitor energy storage system are evaluated,and the efficiency and economy of the system are analyzed.