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Direct torque control of AC motor technology ( Drect torque control, DTC ) is after vector control technology, developed a kind of high performance of AC speed adjustment technology. In recent years, direct torque control technology has obtained great progress, the direct torque control is mainly by controlling the flux amplitude is constant and the stator flux speed to change the stator, rotor flux linkage angle, to directly control the electromagnetic torque, to control the speed of electromotor. Compared with vector control, direct torque control technique which eliminates cumbersome coordinate transformation, Give scientific experiments and production use has greatly convenient and economic benefits.As a new kind of motor speed control mode, there are many issues worthy of study.Papers in the thorough analysis of direct torque control basic principle and on the foundation of basic structure, based on the static coordinate system flux observation model and math model of AC motor, direct torque control model was constructed, and MATLAB software simulation, the simulation results show that the direct torque control effect is good, but there are also large torque ripple phenomenon, to reduce torque ripple, papers put forward by controlling the stator current to optimize the torque ripple of hysteresis current control strategy, simulation results show that the introduction of MATLAB hysteresis current control strategy of direct torque control technique compared with the traditional direct torque control has been greatly improved, the experiment has achieved good effect.Finally, papers further improved direct torque control strategy, and introduces the fuzzy control technology, fuzzy control technology to replace the traditional hysteresis control, realize the torque, flux linkage error of precise control of space voltage vector selection and accurate, through MATLAB simulation test, show that the fuzzy direct torque control system has a good dynamic response, the magnitude of the stator flux is stabilized basically, torque ripple is controlled in a small range.
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