Real-time induction motor velocity controller applying SOSM super-twisting combined with state-feedback linearization

On this paper, a robust velocity controller based on state-feedback linearization technique combined with super-twisting control law, as a second order sliding mode algorithm, is proposed. This closed-loop scheme is applied to a three-phase squirrel cage induction that drives a mechanical load settled by an induction generator which spins above synchronous velocity. The control goals are to regulate the rotor velocity and the squared module of rotor flux linkages that tracks a signal which varies according to stator currents. The controller design is made in aß coordinate frame where the control input signals are conditioned with space vector pulse width modulation to activate the IGBT's of the three-phase converter bridge. The rotor flux linkages are estimated via a reduced-observer by applying sliding modes; meanwhile, the load torque is estimated by an asymptotic reduced-observer. The robustness of the proposed controller is validated through real-time experimentation under extreme test where the velocity reference signal is a pulse train.