Theme of master's work: "System of vector-control by the induction motor with the state observers, estimating the vector of rotor of flux"
The perfection of the systems of control of variable current electrical drive is taking place now and there are wide possibilities to use them.
Thanks to the fact that the induction motor has less moment of rotor inertia, large shifting power on moment and simple construction, than general purpose machine of direct current, asynchronous electrical drive allows to provide the higher fast-acting, than a direct current drive. At present the commonly used systems are with electrical drive on the base of induction motor (IM). This determines the perspective of the similar systems.
Normal work of the modern high-quality systems of asynchronous electrical drive is possible only in the conditions of receipt of reliable information about the condition of object of control (OC). At the same time, while organizing the speed control of IM in the system of co-ordinates d, q, oriented on vector of rotor of flux, the quality of control relies on exactness of measuring or estimation of spatial position of this vector of flux.
Many researches have been lately conducted in the direction of creation of the special devices (identifiers), which allow to calculate the value of vector of flux using the available measurements (phase tensions, currents, control system signals).
A general lack of identifiers is often their high sensitiveness to the change of the parameters of OC (which requires the use additional devices for identification of parameters) and use of non-obvious operations of integration and differentiation, and also upshots of algebraic contours.
One of alternative methods to evaluate the rotor flux vector is to use the state observers (SO), which in case of traditional synthesis do not have indicated drawbacks.
A work purpose is to develop state observers, allowing to recover the value of generalized vector of rotor flux of induction motor with exactness, sufficient both for adjusting the module of vector of flux, and for the orientation of the system of co-ordinates, in which handling signals are formed in case of the induction machine vector-control.
To achieve this purpose next tasks of researches are formulated:
Analysis of existent methods of indirect estimation of rotor of flux of induction machine in case of vector-control.
Working out of the mathematical model OC.
Choice of structure and synthesis of the correcting coefficients OS, allowing to recover the value of generalized vector of rotor of flux IM with the high exactness.
Analysis of static and dynamic properties of the system, closed by estimation of the module of vector of rotor flux and with the indirect orientation on vector of rotor flux.
Working out of practical recommendations on the technical realization of offered observer and system of vector-control on the whole.
Conclusion:
The system of vector-control with the feed-back on the base of flux estimation possesses the high-quality static and dynamic descriptions.
As the errors of estimation of the module and angular position of vector of rotor flux is insignificant in size, it is possible to make a conclusion, that given OS allows restoring the value of rotor flux with the high exactness.
In comparison with other possible variants offered OS for estimation of vector of rotor flux is the most effective, as it has a permanent structure and permanent coefficients and it does not require the special additional means.
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