Siomin A. The method of parameters identification of asynchronous electric drive with low sensitivity to errors of measurement of its mode parameters with stationary rotor

The thesis is devoted to solving the scientific problem of constructing of the algorithms for identifying parameters of the equivalent circuit with low-sensitivity to the presence of errors in the initial experimental data. It is shown that identification of parameters of a T-shaped equivalent circuit of an asynchronous motor with a squirrel-cage rotor in real conditions can be made only when an assumption is used, that reduces the number of unknown parameters (both when taking into account and neglecting losses in the stator steel). The assumption of the equality of L1 and L2 has practically no effect on transient and steady-state processes, which was demonstrated using the root-mean-square deviation of the stator current and the motor speed. The influence of errors in the initial experimental data on the identification of each parameter of the equivalent circuit directly from the expressions for the active and reactive components of the input stator resistance was evaluated. Based on the recommendations received, a system of nonlinear equations was compiled for finding unknown parameters. The influence of the errors in the initial data on the result of solving this system of nonlinear equations is estimated, and recommended values of the supply frequencies of the stator windings for which the acceptable sensitivity of the solution of the system of equations in the presence of errors in the original experimental data is maintained. This provides an identification error of no more than 10% in the presence of an error in finding the input resistance from the stator no more than 5%. It is recommended to perform identification using nonlinear stator supply. The analysis of the relationship of the recommended stator power frequency and motor power was carried out. It turned out that the initial data are best described using a logarithmic equation. Experimental verification of the developed method confirmed the theoretical conclusions. Keywords: parametric identification, equivalent circuit, asynchronous motor, error sensitivity, power frequency.