Engineering, Shahre Kord University
Electerical Engineering, Isfahan University of Technology
This paper presents a new adaptive Sliding-Mode flux observer for speed sensorless and rotor flux control of three-phase induction motor (IM) drives. The motor drive is supplied by a three-level space vector modulation (SVM) inverter. Considering the three-phase IM Equations in a stator stationary two axis reference frame, using the partial feedback linearization control and Sliding-Mode (SM) control, the rotor speed and rotor flux controllers are derived first. These controllers are capable of making the drive system states follow the system nominal trajectories in spite of the motor parameter uncertainties and external load torque disturbance. Then, based on the Lyapunov theory, a SM observer is developed in order to estimate the rotor flux, rotor speed and rotor resistance simultaneously. In addition, in order to satisfy the persistent excitation (P.E) condition, a low frequency low amplitude ac signal is superimposed to the rotor flux reference command. Finally, the validity and effectiveness of proposed control approach is verified by computer simulation.