Speed sensorless direct torque control system of asynchronous motor

This paper designs a new speed-adaptive flux observer which based on model reference self-adapt control system theory. It used stator current and stator flux as state variable, the observation of flux and estimate of speed were proceeding at the meantime. The observed flux could be applied to direct torque control system. In this base the speed sensor less direct torque control emulation system was designed. The speed adaptive scheme of speed estimation was obtain utilizing Lyapunov's stability theory. 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 and speed of motor and robust character of motor stator resistance variety, it can reduce the degree of flux aberration and run characteristic in the low gear.