ADAPTIVE-SPEED IDENTIFICATION SCHEME FOR A VECTOR-CONTROLLED SPEED SENSORLESS INVERTER-INDUCTION MOTOR DRIVE

This paper describes a model reference adaptive system (MRAS) for spee d control of the vector-controlled inverter-induction motor drive with out a speed sensor. The rotor speed is estimated with a full-order ada ptive observer and is used as the feedback signal for the vector and s peed controls. In order to estimate the speed accurately at low speeds , the motor stator resistance is also identified at the same time to c orrect the mismatched resistance value used in the observer. The resul ting system is verified to be hyperstable. As a result, the drive can be operated in a wide range of speed, and especially, it can be operat ed stably at the state of zero speed. Experiments also show that the s cheme is effective.