Information support for process observing flux linkage of the rotor asynchronous motor

Abstract

The article examines the quality indicators of information support of the process of observing the flux linkage of the rotor of an induction motor in vector control systems under the conditions of the action of parametric disturbances. This line of research is intended to provide a solution to the problem of building a high-quality information control system for an asynchronous electric drive, which eliminates the high sensitivity to deviations in the parameters of the control object during its operation. First of all, this refers to temperature changes in the active resistances of the stator and rotor. The obtaining information about the rotor flux linkage is assigned to the observer, which consists of four circuits. In each of the four circuits of the observation system model, two correction signals of thenon-agreement of the stator currents of the asynchronous machine and the observer are introduced through the weighting coefficients. The full vector of correcting feedbacks of the observation system contains in this case eight coefficients. The application of the principles of modal control to determine their numerical values leads to unwieldy equations. The problem is solved more elegant using the direct Lyapunov's method, which makes it possible to determine the possible structure of an observation information system that is stable under parametric disturbances. The numerical values of a part of the coefficients of correcting feedbacks are obtained by the way of the analysis of the quadratic form of the total time-respect derivative of the Lyapunov's function of the synthesized information system. To determine the optimal ranges of variation of the remaining coefficients, numerical methods were used to calculate the roots of the characteristic equation of a closed-circuit observation system. Thus, the idea of the study is to use the largest number of correcting feedbacks in the structure of the observation information system and to select their values using the direct Lyapunov's method and numerical methods to ensure its low sensitivity to deviations of the parameters of an asynchronous machine.