PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems

Discrete models are widely used in the modern world. There are many complex spatially distributed objects and systems, such as transport systems, steelmaking, the wear process of structural elements of bridge structures, cement production, the process of wastewater treatment, and many others. Neighborhood models are used to simulate complex production systems, as well as to manage them. It is the neighborhood models that generalize many discrete systems. In the paper, two simplest classes of neighborhood models are considered, such as linear and bilinear dynamic discrete neighborhood models, which in this paper are presented in a matrix form. The main difference between linear and bilinear dynamic discrete neighborhood models is also shown; explains the discreteness of the neighborhood models. Definitions of such concepts as block multiplication, parametric identification and stability of neighborhood models are given. Parametric identification of the considered dynamic discrete neighborhood models is carried out, formulas for an overdetermined system of linear algebraic equations for performing parametric identification of neighborhood systems are given. The characteristic equation of dynamical discrete neighborhood models is considered in which the eigenvalues necessary for determining stability are found. The stability condition for discrete dynamical neighborhood models is described by the Lyapunov criterion. Based on the results of the stability and adequacy of the neighborhood model of the production spatially-distributed system, one can judge the possibility of using this model for forecasting its states. A program was developed for constructing and investigating discrete dynamic neighborhood models for stability by the Lyapunov criterion. This program was implemented in the programming block of the mathematical package Mathcad. A block diagram of the program algorithm is presented, which shows the sequence of operations for parametric identification and study of linear and bilinear discrete neighborhood models for stability by the Lyapunov criterion. The main steps and commands in the Mathcad environment that were used during the writing of the program code are described in detail.

Intensive development of systems with permanent magnets requires improvement of their calculation methods. At present, it is impossible to create Electromechanical devices with high mass-energy indicators without accurate methods of field calculation and optimization calculations. Thus there is the following technical contradiction. Accurate electromagnetic calculations require significant computational resources and the use of complex programs such as Ansys, Cosmos, and optimization methods require a large number of calculation cycles when choosing the best parameters. It is not possible to include heavy-weight programs in optimization cycles, despite their accuracy, because of the unacceptable calculation time.This contradiction can be solved in only one case: it is necessary to create a simple but accurate model for the calculation of the magnetic system, which could be used for optimization. The article offers a solution to this problem. A technique based on the finite element method is proposed, but a pre-selected limited number of elements providing the required accuracy is used to implement this method. This is a new approach to solving such problems.Thus, the method is simple in terms of implementation, but acceptable in terms of accuracy of calculation of the basic electromagnetic parameters. It has been tested for optimization models with a large number of cycles in the design of permanent magnet systems and has shown very good results in counting time and accuracy. The method used in the design of magnetic systems of generators of wind power installations, gate motors, shutoff devices, generators for diesel-electric installations of uninterruptible power supplies This approach can be recommended for solving other similar problems: thermal, ventilation, hydraulic, dynamics of stress.

There is a question of cooling liquids that are used in the production or obtained as a result of the work of other plants in any industrial enterprise. To solve this problem, there are special air coolers -cooling towers. Cooling towers are mainly used in water recycling systems for cooling heat exchangers at present. The analysis of the current state of the PCS of the circulating water cooling system at BOV-6 is performed in this work. PCS has been modernized according to the results of the analysis. Thefollowing tasks performed with the help of PLC Allen-Brabley CompactLogix: - algorithms of automatic start-up of fan electric motors in the cooling tower were developed depending on their operating time and on the temperature in the cooled water collector KOV-1; - algorithms for controlling pneumatic cut-offs on the water supply pipelines to each section of the cooling tower were developed with the possibility of controlling them from the HMI screen; - algorithms for controlling the electric valves on the water supply pipes from the sections to the chilled water collector were developed which are controlled from the mnemonic scheme; - the algorithm of regulation of two valves on the feed line with the BHO and Kama was developed with the aim to minimize the financial costs of water consumption; - HMI screen of process control of BOV-6 was developed. The algorithm of automatic start-up and stop of cooling towers taking into account operating-out of the equipment, the algorithm of maintenance of level in the reservoir of the cooled water is developed and realized. The necessary HMI screen of process control of BOV-6 was developed. Algorithms, programs and mnemonic schemes are prepared for implementation at the actual operating facility BOV-6 and will reduce the load on the operator by automating some of its functions, such as maintaining the temperature and level in KOV-1, as well as automatically activating the sections of the cooling tower. At the same time, the dynamic equipment of the cooling tower will be evenly worn out.

A robust approach to controlling the process of titanium reduction is considered, which makes it possible to intensify the process by increasing the temperature. The control object is the exothermic reaction zone of the industrial titanium recovery apparatus, represented by the control object with interval-indeterminate parameters, the set temperature value of which is maintained by the on-off regulator. The technological limitation of the value of the maximum temperature of the control object is determined. A description of the object in the form of an interval dynamic model is obtained. Using the model in the class of two-point systems, an analysis of robust quality and synthesis of robust control of the temperature of the control object was carried out. The analysis of robust quality provides the definition of the worst performance indicator of a two-position temperature control system for any values of object parameters from known intervals. Such an indicator is the maximum possible amplitude of the positive temperature deviation, characterizing in the two-position system the magnitude of the excess of the setpoint set by the temperature. Synthesis of robust temperature control is based on the concept of guaranteed (minimax) control, suggesting the achievement of the best result with the worst combinations of uncertain factors. Its application allows the on-off regulator to robust properties to maintain the maximum permissible temperature of the control object, which are provided by using the amplitude of the positive temperature deviation as a guaranteed criterion for estimating the operation of the two-position system. The task of synthesis of robust control is to find such a given value for a two-position controller that would guarantee the maintenance of the maximum permissible temperature of the object if there are undetermined factors in the interval model. In this formulation of the problem, the set value of the on-off regulator is the guaranteeing control of the temperature of the object. The article considers the evolutionary way of solving the problem of intensification of the restoration process, which involves the development, based on the interval dynamic model and practical implementation of the proposed methods of robust temperature control at different stages of automation of sponge titanium production with the use of centralized control machines, control computers, microprocessor controllers and computers. Robust control allowed to increase the temperature and improve the technological parameters of the process of reduction of titanium tetrachloride with magnesium.

The analysis of various types of reactive electric tanks of the most frequencies used in an adjustable electric drive is presented. On the basis of the analysis, it has been shown and proved that the reactive machine with anisotropic magnetic conductivity of the rotor has the best energy, weight and size, and operational characteristics among various types of jet electric machines and the most popular asynchronous electric machine. The results of experimental studies of jet machines with anisotropic magnetic conductivity of the rotor (SynRM) with installed capacity from 1.5 kW to 500 kW, as well as approbation of the design and control theory of a reactive electric machine with anisotropic magnetic conductivity are presented. The design and manufacturing technology of a prototype rotor model of a reactive machine with anisotropic magnetic conductivity with longitudinal loading is described in detail. A comparison was made of the results of studies of reactive electric machines, in which the properties of the anisotropic magnetic conductivity of the rotor were obtained by its longitudinal and transverse blending. According to the results of experimental studies, various graphs of the operating characteristics of the electric drive were constructed. The study of the dynamic properties of the electric drive with SynRM. The timing diagrams of the start-up of the investigated electric machine are given. The results of thermal tests allowed us to establish the limiting possibilities inherent in the design of a prototype machine with a nominal installed capacity of 500 kW. A comparison of the prototype of a reactive electric machine with the anisotropic magnetic conductivity of the rotor with an asynchronous machine in terms of specific power. Studies and tests allowed verification of theoretical studies and the developed design methodology of SynRM and showed their adequacy.

Eight-port networks of various versions, including an eight-port network with two input and six output terminals, are necessary to replace some energy facilities. Especially when only the input and output characteristics of electrical energy are of interest. Features of the state of the eight-port network are described by equations of various forms. To describe the state of an eight-port network with two input and six output outputs in power engineering, the A-form equations are most often used. In addition, the equations of the B-form, G-form, H-form, Y-form and Z-form are used. The equations of these forms are presented in the article. And for the implementation of these equations it is necessary to have information about the numerical values of the corresponding coefficients. They can be determined experimentally. It is enough to experimentally determine the coefficients of the equations of any one form. The method of this definition is known. The coefficients of equations of other forms can be determined analytically. For this, it is necessary to have an idea of the quantitative relation of the coefficients of equations of various forms among themselves. The proposed article is dedicated to the identification of such a connection. The article presents a method for identifying such links. It was found that it is advisable to take the B-form equations as basic equations. It is with the coefficients of the B-form equations that describe the quantitative relationship between the output and input characteristics of electrical energy in a passive eight-terminal network with two input and six output outputs. It is most convenient to establish a connection between the coefficients of the A-form, G-form, H-form, Y-form, and Z-forms describing the state of the same eight-port network. Formulas are established that establish a quantitative relationship between the coefficients of the B-form equations and the coefficients of the A-form, G-form, H-form, Y-form and Z-form equations describing the state of an electric power object, replaced by a passive eight-pole network with two input and six output pins. The presented method of forming a quantitative relationship between the coefficients of equations of various forms can be extended to other types of multipoles. Such a connection will significantly increase the possibility of using multipoles in engineering practice.