The Research Of Asynchronous Motor Direct Torque Control System

Asynchronous motor is indispensable in modern industrial power plant, its high performance speed control and intelligent control has become the research focus in the field.Direct torque control, as following the vector control technology and a new kind of high performance control scheme, due to its own means of control directly, good robustness, fast system accordingly, has the advantages of good dynamic and static characteristic, so it appears immediately attracted extensive attention of the personage inside course of study.This paper first introduces the development situation of the ac(alternating current) technique, and then on the basis of dynamic mathematical model was build up the principle diagram of direct torque control system are analyzed, and then discussed with what kind of simulation software and the simulation algorithm, for traditional simulink built-in ode45 algorithm to do the improvement in the runge kutta method, after considering solving speed, since the launch of the execution time, whether and factors such as accuracy, we adopted the runge kutta method ode4 algorithm, simulation algorithm in this run, make our simulation system run faster, smaller error.In counter rotating torque and flux estimation model analysis process, this paper compares several kinds of estimation model, the most common considered integrated the advantages of them, the final design U- I model of flux torque estimation.Due to the torque of the motor running is very important, the traditional two point zero torque controller in speed or falls suddenly, circular flux serious distortion, so in order to better control of the motor, we designed a three point torque controller, and on the selected voltage vector, in order to better control of counter rotating moment, must be conducted on the basis of the torque is achieved by.In this paper, in addition to the theoretical analysis of direct torque control system, also for the designed system are simulated in MATLAB/SIMULINK software, the results show that with the improvement of the three-point torque regulator used in the simulation of speed in achieve stable speed time than the traditional two point shorter the time needed for torque regulator, in the simulation of the stator flux linkage, the improved torque controller is not only the time greatly reduced, and the simulation result of the it from center, counterclockwise, amplitude is more and more big, finally form a smooth round, it’s basically meet the requirements.