Development of direct torque controller for the ho

  • Detail

Research of direct torque content system of induction motor in oil extractor Xue Yan1, Yan PO2 (rthwest Electric Power Design Institute, Shaanxi Xi'an 710032, China; aanxi Huanghe Group Inc., Shaanxi Xi'an 710043, China) abstract:a large number of oil extractor are used in oil field, Because of all these equipment's electric motor running effective CY is very low, a great deal of electric energy is the present time many technology of saving energy method be used, but the effect is not satisfacio e text introduce the direct torque control technology to solve the question o f electric motor low efficiency, the effect is very satisfaction. The workbench moves in a straight line along the Y axis keywords:oil extractor; induction motor; savingenergy; At present, there are about 110000 organic production wells in oil fields across the country, of which pumping wells account for more than 90%, 65% of liquid production, and 75% of oil production is produced by pumping units. The number increases at a rate of 10% every year. It is the main way of oil production in oil fields. At the same time, it is also a major energy consumer, and its energy consumption accounts for 1/3 of the total energy consumption of oil fields. Therefore, reducing the energy consumption of pumping units, improving system efficiency and reducing oil production costs have become the main tasks for oil fields to achieve energy conservation and efficiency

pumping unit motors generally use three-phase asynchronous induction motors. At present, a variety of energy-saving technologies have been adopted for pumping unit motors, which can be summarized as follows

(1) replace the energy-saving motor; (2) Connect compensation capacitor in parallel; (3) Adopt voltage regulation device; (4) General frequency converter is adopted

after adopting the above energy-saving measures, the operating efficiency of the pumping unit motor has been improved. However, due to the factors such as fast torque change, wide torque change range, balance affected by well condition change, and power generation state, the long-term power saving effect is poor, and the average comprehensive power saving rate is generally less than 5%

in view of this situation, the author adopts the latest motor direct torque control principle, combined with the operating conditions of the pumping unit motor, and develops a pumping unit motor direct torque controller to improve the comprehensive power-saving efficiency of the pumping unit motor

The direct torque control (DTC) theory of motor was first proposed by Professor depenbrock of Ruhr University in Germany in 1985. This is a new breakthrough of AC motor speed regulation theory after vector control. It uses the space vector analysis method to calculate the motor flux and torque directly in the stator coordinate system, and generates PWM signals by the bang bang control of flux and torque, so as to select the best switching state of the inverter, so as to obtain efficient dynamic performance

2 principle of direct torque control

direct torque control is stator field oriented, so it is established in a static coordinate system( α,β) Up. The transformation formula of each stator quantity is as follows:

where: Xa (T), XB (T), XC (T) are the instantaneous values of the corresponding stator quantities, X α (t),X β (t) Yes( α,β) Two components in the coordinate system

the core of direct torque control is flux control and torque control. The control principle block diagram is shown in Figure 1

when controlling, the first goal is to remove the surface damage caused by the inoculation of the few layer graphene conductive slurry of lithium battery developed by rough polishing company, measure the DC bus voltage and stator current, and then decompose them into α,β Direction, and calculate the actual flux linkage value and torque value in these two directions. As feedback, it forms a closed loop with flux setting and torque setting respectively. Bang bang control is carried out to generate flux linkage and torque request signals. At the same time, it also calculates the sector position of the flux linkage. Finally, through torque request, flux linkage request and flux linkage sector, the inverter switch optimizer sends out optimized PW m signals, Drive the output voltage of IGBT to control the motor

3 system composition

the system composition is shown in Figure 2. The figure includes the main circuit and control circuit. The main circuit inverter adopts Ig BT power tube; The core of the control loop adopts DSP processor, which has the ability of high-speed data calculation and processing, and can meet the requirements of high-speed real-time calculation of DTC

4 field operation effect

the amcs100 pumping unit motor direct torque controller developed based on the principle of direct torque control has been installed and operated on the third oil mine, and pumping unit wells of the seventh oil production plant of Daqing Oilfield. After detection, under the original operating conditions (stroke and stroke) unchanged, the active power saving rates are 30.51%, 20.96% and 14.52% respectively; The reactive power saving rates are 97.74%, 97.88% and 96.11% respectively; The power factor is 0.989, 0.992 and 0.987 respectively; The comprehensive power saving rates are 39.35%, 29.71% and 21.60% respectively, with remarkable energy-saving effect. In terms of power saving effect, wells with heavy average load and power generation state have a high power saving rate; For well balanced wells with basically no power generation, the power saving rate can also reach more than 20%

5 conclusion

applying direct torque control technology to the motor control of pumping units has the characteristics of fast dynamic response speed of torque regulation. Torque and flux linkage can be controlled separately, which is easy to suppress the generation of power state. After practical operation, remarkable energy-saving effect has been achieved. It is of great promotional value

references [1] Wu ShouZhen, Zang Yingjie Pulse width modulation control technology of electric drive [M] Beijing: China Machine Press 2 〕 Li Su Direct torque control technology of asynchronous motor [M] Beijing: China Machine Press 3) Fu Xi System optimization and control [M] Beijing: China Machine Press 4 〕 Wang nianxu DSP foundation and application system design [M] Beijing: Beijing University of Aeronautics and Astronautics Press

Copyright © 2011 JIN SHI