A speed sensorless vector control of induction motor operating at high efficiency taking core loss into account

This paper proposes a speed-sensorless vector control method for an induction motor operating at high efficiency and high response, in which core loss is taken into account, and discusses the system's performance. The proposed vector control system consists of a speed-adaptive rotor-flux observer which takes core loss into account and employs a direct-field-oriented control scheme which compensates for the influence of core loss. On the basis of simulation and experimental results, the authors show that the proposed system can estimate motor speed even when the rotor flux is changed.