Adaptive Estimation of Speed and Rotor Time Constant for the Vector Controlled Induction Motor Drive Using Reactive Power

Model reference adaptive system (MRAS) -based techniques for the estimation of speed and rotor time constant for induction motor drive are presented in this paper. The proposed methods use both the instantaneous and steady state reactive power to formulate the error signal. The use of instantaneous reactive power (IRP) in the reference model makes it completely free from the machine parameters. On the other hand, the choice of steady state reactive power (SRP) in the adjustable model eliminates derivative terms from the same. Therefore, the accuracy in the estimated quantity is improved. It is important to mention that the flux estimation is not required in any step of the computation. Moreover, the system is independent of stator resistance variation, as the reactive power is considered in the MRAS. The stability of the proposed MRAS is achieved by applying Popov´s hyperstability criterion along with proper manipulation of different error signals. Simulation results and the corresponding experimental results have been presented to validate the method.