Research And Realization Of Speed Sensor-less Direct Torque Control Of Induction Machine

Direct torque control (DTC) technique has developed since the 1980, It is a newly high-powered AC drive control technique after the vector control technique. DTC directly calculate and control the torque of AC drive in the stator reference frame. By using stator field-orientation, the optimum switching mode is achieved to control the inverter. DTC suffer the widespread concern and the quick development because of it's novel control thought, manifest system construction and well stationary and dynamic characters. But the low-speed performance of the DTC is not good, and the use of speed-sensor increase the cost, reduce the reliability of the system.A flux linkage observer and fuzzy controller are combined, they are used in induction motor replace the classical simple integrator in the direct torque control system. The results of the MATLAB emulate and the experiment make out that the track of the"stator flux approach circularity, thereby the scheme improve the performance of the low-speed, the pulsation and the electromagnetism yawp are well restrained. This paper adopt the model reference adaptive system to calculate the speed of the AC motor, which is proved stabilization by Popov's theory. Considering the effect of the stator resistance, this paper introduced the reactive power model. The experiment results show that these methods can get speed, which approximately to the real speed of the motor, strengthen the robustness of system, and widen the speed range of drive system.Author using the TMS320LF2407A which is specialized controlling machine, devised a set of experiment equipment on which to implement DTC of the AC motor. The real-time controller software is written by assemble language, the research of digital realization and the software design is carried out deeply. All the notions and designs above are confirmed in the DSP test-bed for experimentation and development of motor control.