Robust TDOF controller of induction motor without speed sensors for variations of rotor resistance

This paper describes the speed sensorless vector control of an induction motor using two degrees of freedom (TDOF) theory. A TDOF control design which robustly stabilizes the plant, guarantees robust H _∞ performance in terms of a feedback controller and has a good tracking performance in a feedforward controller is presented. In this paper, an induction motor drive control system which is robust to variations of rotor resistance and improves the tracking performance is constructed. An adaptive flux observer is used for the purpose of estimating rotor flux and speed in the speed sensorless scheme. Experimental studies verified the validity of the proposed algorithm