A Lyapunov based nonlinear speed tracking controller for Synchronous Reluctance Motor using adaptive input-output feedback linearization technique

This paper describes a Lyapunov based nonlinear speed tracking controller for three-phase synchronous reluctance motor (SynRM) for different control strategies corresponding to this motor. Assuming a linear magnetic saturation, ignoring the motor iron losses, the proposed nonlinear controller is designed on the basis of adaptive input-output feedback linearization technique and is tested by computer simulation. The simulation results obtained confirm that the desired speed reference command is perfectly tracked in spite of uncertainty and mismatching that usually exist in the stator direct axis inductance (Ld) due to the magnetic saturation. These results also show that under persistency of Excitation (PE) condition and for each of control strategy, chosen for this motor, the errors in the stator direct and quadrature axis currents exponentially converge to zero while the error in parameter Ld also asymptotically reaches to zero. One may note that in three-phase SynRM, the variation of stator q axis inductance (Lq) with the magnetic saturation is small and that can be ignored for motor different modes of operating conditions.