AC Motor Speed Control System Study Based On Fuzzy Direct Torque

Induction motor is widely used in the field of oil production. In all production aspects of Oilfield, oil drilling, oil extraction, oil and gas transportation, we require asynchronous motors to power. In the oil drilling process, it is often need to adjust the motor speed at different times depending on the depth and geological structure formation. The needs required down-hole pressure and flow rate of the motor speed control. In terms of oil and gas transportation, due to the unstable pump load, this requires speed control system has good disturbance rejection. Speed control system for research, not only conducive to the production of oil, but also you can also optimize the efficiency of the inverter, implement energy saving effect.In terms of speed control system control structure, this article will not direct torque and speed sensor combined. Direct torque control means direct, fast system response, good robustness and excellent dynamic and static properties and other characteristics, and the combination of speed sensor system can be further miniaturized. Conducive to the effective use of oil production in space, in addition, another traditional method of speed sensor has been improved, the main method for the reference model. In comparison with the basic model adjustment, the proportional coefficient of the PI regulator line setting to improve the rapidity and accuracy of speed detection.For control methods, PI is simple, easy to understand, clear meaning of the parameters, but nonlinear system is not ideal. Fuzzy Control of anti-disturbance is strong, but larger slip. And general fuzzy self-tuning PI control parameters are hard to set. In this, the load characteristics, and characteristics of induction motor. Uses fuzzy PI controlled in parallel, PI control at speed error is large, so that the rotational speed changes rapidly. In small error, fuzzy control can increase the disturbance rejection. While the PI segment to segment the limiter to increase the speed range, the fuzzy part of the string into the wavelet transform to reduce the static error.Improved fuzzy PI speed senseless direct torque system was designed. Full account of the rapid response, control of the control indicators overshoot, etc. Through modeling and simulation MATLAB analysis, Demonstrated improved control system and stability in the fast indeed has a significant advantage.