Complete parameter estimation of induction machines by time-varied parameters

This paper proposes a method to find the equivalent circuit parameters, moment of inertia, and friction coefficient of an induction machine. The reference data include time-varied signals of voltage, current and rotor speed. By the time-varied voltage and current, a time-varied impedance can be found. The parameters of equivalent circuit can be found from the variation of impedance to the rotor speed. And then, the torque can be found via dynamic system model and rotor speed. From the torque and rotor speed with time, moment of inertia and friction coefficient of the motor can be obtained, too. The least mean square method is used to solve the above parameters in this paper. The initial values of least mean square are also described. The comparison of the simulated performance in starting states of an induction machine with the real one is discussed in this paper, accordingly, practicability and accuracy of this method has been proven.