A current-based output feedback mode control for speed sensorless induction machine drive using adaptive sliding mode flux observer

This paper presents a new adaptive sliding mode flux observer for speed sensorless and rotor flux control of induction motor (IM) drive supplied by three-level space vector modulation (SVM) inverter. Using the induction machine equations in the stator two-phase stationary reference frame, based on partial feedback linearization control method, the sliding mode speed and rotor flux controllers are derived first. These controllers guarantee the asymptotic tracking of the pre-specified speed and rotor flux command references in spite of the motor parameter uncertainties and load torque disturbance. Then, the sliding mode flux observers are developed to estimate speed, rotor time constant and the rotor flux quantities simultaneously. In addition, to satisfy the persistent excitation (P.E) condition, an ac signal component is superimposed to the rotor flux reference command. Finally, a digital simulation study is carried out and some simulation results are presented to show the validation the effectiveness of the proposed control approach.