A Speed Sensorless Sliding-Mode Controller for Doubly-Fed Induction Machine Drives with Adaptive Backstepping Observer

In this paper, a novel nonlinear speed sensorless control scheme is presented for doubly-fed induction machine drive (DFIM). The proposed controller Is designed on the basis of input-output feedback linearization and sliding-mode control with adaptive backstepping observer. Considering the DFIM fifth order model in a stator two axis reference frame with rotor fluxes (psi _dr ,psi _qr ) and stator currents (i_ds, i_qs ) as state variables, an ideal tracking controller is first designed which is capable of following a desired reference model. It is shown that the ideal controller can perfectly track the active and reactive powers reference signal that are injected to the stator circuit. However in the motoring mode of operation, the tracking signals are the rotor speed reference signal and the reactive power reference signal that is injected to the stator circuit. Then in order to remove the rotor speed mechanical sensor and making the drive system performance robust with respect to the stator and rotor resistance variation, an adaptive backstepping observer is designed which online detects the mentioned quantities. The nonlinear observer stability is proved by Lyapanouv theory. Finally, the validity and effectiveness of the drive system control method is demonstrated by some simulation results.