Adaptive speed identification scheme for vector controlled speed sensor-less inverter-induction motor drive

A model reference adaptive control system is described for a speed sensorless control of the vector controlled inverter-fed induction motor drive. The rotor speed is estimated with a full order adaptive observer and is used as the feedback signal for the vector control and the speed control. In order to estimate the speed accurately at low speeds, the motor stator resistance is also identified at the same time to correct the mismatched resistance value used in the observer. The approaches are verified to be hyperstable. As a result, the drive can be operated in a wide range of speed, and can be operated stably at zero speed. Experimental results show that the scheme is effective.<<ETX>>