Convergence and stability analysis of IM rotor time constant estimators based on MRAS scheme

In this paper, the convergence and the stability analysis of two Induction Motor (IM) rotor time constant (T
_r
) estimators are performed. Both estimators are Model Reference Adaptive System (MRAS) based, first considering the rotor flux vector, second the reactive power as the state variable. The stability analysis is based on Lyapunov and Popov criteria, passivity formalism and positive real function concept. Performances and asymptotic stability of both estimators for selected adaptive mechanisms are demonstrated through computer simulations using dynamic model of vector controlled IM drive.