Direct Torque Control Based On Mras Asynchronous Motor Speed Sensor,

This paper designs a new speed-adaptive flux observer which based on model reference adaptive control system theory. The observation of stator flux and estimate of speed were proceeding at the meantime, the observed stator flux could be applied to direct torque control system. The paper emphasize expound two keystone parts in design, which are stationing the pole of flux observer and selecting plus matrix. With regard to station the pole of flux, the author adopt a sort of simple and convenient means, which is in virtue of MATLAB, and finally find aim gain matrix. the reference observer is based on motor state space equation, which used stator current and stator flux as state variable, motor itself as reference model, the designed observer as modulation model, speed observer as modulation parameter. Because the state equation's state variables are stator current and stator flux, the stator flux can be observer direct. After defining Lyapunov's stability theory the speed self-adaptive scheme is confined. And then the speed sensor less direct torque control emulation system was designed. The proving of stability theory condition ensures the system is steady. The voltage fall of stator resistance can also affect the precision of speed observer when in very low speed although the observer has perfect robust trait, so the stator resistance is observer at the same time. Which make sure the system has perfect characteristic to stator resistance change even in the very low gear.Based on the element and S-function in SIMULINK, the simulation former of speed sensor less direct torque control system was set up. The emulate experiment results indicate that this system is perfect , such as the speed estimate is quick and nicety, The arithmetic is simple, all this is easy to implement on line. And also the system has preferably observe precision of stator flux even in the low gear, so the control character of motor can be improved. The torque dynamic respond is quick, so the limitations of error accumulate and zero point excursion which is on simple integrator can be conquer. At last, it discusses a scheme, which is the speed sensor less direct torque control system of asynchronous motor is digitized realization based on the controller's core is TMS320F2812.