Research On Energy Recovery Of Electric Feedbackand Speed Control In Hydraulic Pumping Units

Pumping unit is an important production equipment in the petroleum extraction industry.With the development of oil fields in the middle and late stages in recent years,the environment has become increasingly complex.It is an inevitable trend for pumping units to develop in the direction of energy conservation.Although the traditional beam pumping unit has the advantages of simple structure,convenient maintenance,safety and reliability,the biggest shortcoming of it at present is that the energy consumption is too large.Therefore,research and development of energy-saving pumping units is a major problem that the oil industry needs to solve urgently.The secondary regulation technology can effectively recover and reuse energy,so researching the hydraulic pumping unit based on the secondary regulation technology is the research direction of the current industry,and the energy saving effect is significant.The pumping unit researched in this paper is mainly based on the secondary regulation hydrostatic transmission technology.It uses the combination of the secondary element pump-motor and the electric energy feedback unit to realize the energy recovery and reuse by switching the working conditions of the pump motor and the doubly-fed asynchronous motor.First,the working principle of the hydraulic system of the secondary adjustment-electric feedback hydraulic pumping unit was analyzed;The main process parameters such as suspension load,stroke and stroke times of the hydraulic pumping unit were analyzed and calculated;According to the design requirements of working conditions,parameter calculation and selection of key components of the system were carried out.Secondly,the simulation model of the hydraulic pumping unit system in AMESim was established.According to the principle of the system,the variable frequency feedback unit was designed as a dual PWM converter control method that can realize the bidirectional flow of current,and the flow control strategy of the variable pump motor at the main shaft variable speed.Each part of the system was simulated separately to verify the feasibility of the control method of each component and analyze the energy-saving effect of the electric feedback hydraulic pumping unit system;The limit position control strategy of the sucker rod was determined to limit the displacement to a certain range;The single variable method was used to analyze the influence of different suspension point load,stroke,pump motor rated displacement,motor and other system parameters on the working condition and energy-saving characteristics of the pumping unit.Finally,the flow characteristic curve of the pump motor was optimized by adding the BP neural network PID intelligent control strategy.Thereby the speed fluctuation of the sucker rod during commutation was reduced.And finally achieving the purpose of optimizing the speed characteristic curve of the sucker rod.