## No 33 (2020)

**Year:**2020**Articles:**12**URL:**https://ered.pstu.ru/index.php/elinf/issue/view/219**DOI:**https://doi.org/10.15593/.v0i33

Articles

ANNIVERSARY OF THE «AUTOMATION AND TELEMECHANICS» DEPARTMENT: HISTORY, PEOPLE, PROGRESS, PERSPECTIVES

#### Abstract

In this article the main stages of the formation and development of the department «Automation and Telemechanics», celebrating the 60th anniversary of its founding, are presented. The history and people who made the most significant contribution to the creation of the department are described. A brief description of the areas and specialties of training implemented at the department, as well as the main results of educational and research activities are presented.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):7-20

METHODS FOR IMPROVING THE QUALITY OF SYNTHESIZABLE VOLTAGE OF THE CASCADE FREQUENCY CONVERTER

#### Abstract

In connection with the development of the industrial complex, the development of new technologies, the increase in the extraction and processing of natural resources, as well as the study of new territories, there is a widespread use of a controlled electric drive and various types of electric energy converters in the world electric power industry, as well as a steady growth trend in their installed power. For these reasons, the issues of electromagnetic compatibility of the load with the supply network and ensuring the required quality of the converted electricity are particularly acute. A decrease in the quality of the converted electricity leads to a deterioration in energy performance, a decrease in productivity, a reduction in the life of electrical equipment, as well as an increase in the likelihood of an emergency. One of the effective ways to solve this problem is to use a cascade frequency converter, which allows the synthesis of high quality output voltage. Purpose: the development of circuit solutions and control algorithms for a cascade frequency converter that will allow the synthesis of high quality output voltage. Methods: on the basis of number-theoretic methods, theoretical foundations of electrical engineering, fundamentals of power electronics and positional number system, the study of options and ways to increase the possible number of levels of instantly synthesized voltage at the output of a cascade frequency converter was carried out. Results: proposed circuit solutions and control algorithms for a cascade frequency converter, which will improve the quality of the synthesized voltage. A mathematical description of the control algorithms of the unit cells of the cascade frequency converter, allowing to synthesize the required voltage. A quantitative and qualitative comparison of ways to improve the quality of the synthesized voltage at the output of a cascade frequency converter is presented, a histogram of the dependence of the number of synthesized voltage levels on the unit cell construction scheme, the number of cells and control algorithms is shown. The result of mathematical modeling of the phase voltage at the output of a cascade frequency converter synthesized using three two-level cells with differentiated supply voltage and control algorithms with summation and difference of cell voltages in phase is presented. Practical relevance: the proposed schemes and methods for improving the quality of the synthesized voltage at the output of the cascade frequency converter and the results of the studies can be used in the design and development of electric power converters with high quality output voltage. This allows you to increase energy efficiency and significantly improve the harmonic composition of the synthesized voltage.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):21-45

IMPROVEMENT OF RELIABILITY OF THE IMPROVED BRUSH-COLLECTOR ASSEMBLY OF THE DC MOTOR OF THE MOBILE COMPOSITION

#### Abstract

This article is sanctified to the problem to technical diagnostics on a public electric transport and electrical equipment. By reason of absence of methodologies of timely control of the state of brush-collector knot (BCK) and acceptance of measures on renewal of the capable of working state, about 50-60 % comes in uselessness, not working to the complete term of exploitation. Perfection of construction of BCK, development of new and improvement of existent methods of increase of reliability of exploitation of BCK, is the actual task sent to the increase of longevity and faultlessness of work of electric motors on the whole. Purpose is to develop the improved brush-collector knot of electric motors of direct-current with enhances able reliability. Methods used for creation of mathematical model and development of methodology for estimation the electric motors refuses intensity and hardware takes into account all lacks of the considered analogues and allows to carry out monitoring on refuses and disrepairs of BCK of electric motors during work on a rolling stock. Results basic reliability indexes of BCK were expected. A mathematical model is worked out for the exposure of types of refuses of brush-collector knot taking into account his technical descriptions (size of pressure, beating, amplitude of vibration) influencing on reliability indexes in the process of exploitation. The scrutinous of efficiency of functioning of improved BCK electric motors program is worked out with enhance able reliability in the process of exploitation for the extension of his time of service. Practical relevance: the offered model on the basis of research of types of refuses of brush-collector knot of electric motors is worked out the improved construction of a brush knot, that allows to increase the resource of brush and bring down expenses on technical maintenance of electric motors in the process of exploitation. Recommendations offer for passing to repair of electric motors on the actual state for a rolling stock.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):46-60

«BILLIARD» COMPUTER’S LOGIC

#### Abstract

Currently, research is actively ongoing in the field of quantum computing, quantum computers. Most likely, quantum computers, as it was already in the history of science many times, is not a panacea, but will occupy its niche on a par with conventional calculators. Moreover, in this area there are some features that can be used in binary logic. We are talking about the so-called reversible calculations and special elements, for example, Fredkin’s elements. Purpose: development of a methodology for studying billiard logic circuits in practical classes, development of thedevelopment of a decoder and a memory element, Fredkin element for use in laboratory classes. Methods: The analysis of the billiard full adder, the synthesis of thedecoder and a memory element, Fredkin element based on the LUT FPGA. Results: The study tested in detail the steps of an example of such calculations and offers an element for their implementation in binary logic.Thecircuit operation of the “forward” and “backward” using the symbols of “billiard” balls is analyzed.Decoder and memory element developed,Fredkin element based on the LUT FPGA. Running simulation in NI Multisim, the system of the company National Instruments Electronics Workbench Group circuit simulation, confirming the workability of the proposed gate. Practical relevance:a technique for studying billiard logic circuits is useful in practical exercises; the developed Fredkin element can be used in laboratory classes.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):61-77

DEVELOPMENT OF THE MATHEMATICAL MODEL OF THE ASYNCHRONIZED SYNCHRONOUS WIND GENERATOR FOR THE PROBLEM OF OPTIMIZATION OF THE BASIC GEOMETRIC DIMENSIONS BASED ON GENERALIZED VARIABLES

#### Abstract

The use of a double-fed electric machine as the main power generator is one of the main areas of development of wind energy. This class of electric machines has been known for a long time, but their use for wind power plants (wind turbines) is a new technical solution. To be able to optimally design this type of generator, it is necessary to develop new methodologies. The article shows one of the approaches to the optimal design of a double-fed generator as applied to wind turbines. Purpose: development of a mathematical model of an asynchronized synchronous wind generator for the task of optimizing the basic geometric dimensions based on generalized variables. Methods: creating a mathematical model of the generator, in which the geometric dimensions of all the elements of the cross section of the magnetic circuit will be described using generalized variables. These variables provide a dependence and an accurate description of the dimensions of the elements of the magnetic circuit from each other. Results: On the basis of the proposed mathematical model, a methodology for synthesizing options for solving the problem of optimizing the basic geometric dimensions of a double-fed machine is built. This technique allows, with a limited amount of input data for designing, to calculate all elements of the magnetic circuit and then make a complete calculation of the electric machine, with geometry optimization using the Gauss-Seidel coordinate descent method when moving towards the optimum in combination with the Fibonacci method when choosing a step. Practical relevance: This technique is implemented in the Delphi software environment and used to design double-fed generators. It allows the developer to significantly reduce time and labor for the synthesis of optimal design options for the active parts of the double-fed machine, while ensuring sufficient accuracy of calculations.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):78-98

IDENTIFICATION OF PARAMETERS IN A DYNAMIC MODEL OF A HEAT EXCHANGER

#### Abstract

Thearticle substantiates the necessity of developing mathematical models of heat exchangers. A review of the methods of parametric and non-parametric identification of heat exchangers based on experimental data, as well as on material and heat balances is given. The author discusses advantages and disadvantages of these methods. The input, output, and intermediate parameters are selected as the main parameters of the object of study (shell-and-tube evaporator of the oil stabilization unit). The statement of the control problem is given. A mathematical model of the evaporator is developed in the form of a heat balance in a differential form. The coefficients in the heat balance equations are expressed through technological and design parameters. A transition was made from the obtained system of ordinary differential equations to expressions in the form of a system of transfer functions over various channels. The possibility of constructing a mathematical model of the studied object with the adjustment of the coefficients in the model using the experimental data of the current unit was suggested. The initial data were obtained from the trends of the process parameters. The resulting automatic control system is implemented using the tools of the software package Simulink. The search for coefficients in the model according to the selected criterion was performed using the fminsearch optimization function. As the initial search conditions, pre-calculated values of the coefficients of the model, presented in the form of heat balance, are accepted. The quality of the model was estimated by the average relative error of approximation. The proposed method for identifying the parameters of a dynamic shell-and-tube evaporator model improves the accuracy of the models. Research results were obtained using the Matlab software package. The proposed model of the object can be applied in the development of simulators, the study of the operating modes of the system, and in process control using mathematical models.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):99-114

IDENTIFICATION OF THE TIME CONSTANT OF DC MOTOR ROTOR

#### Abstract

In modern control systems, there is an upward trend to increase its algorithmic (software) part and, accordingly, to decrease the hardware part. With this approach, an object model is used, the accuracy of which significantly affects the quality of processes in the system. Therefore, the development of methods for finding the parameters of control object is very promising. Thus, in the absence of direct feedbacks in the drive control system, the determination of the required state variables can be carried out indirectly by the object model. Accuracy of the rotor circuit model of DC motor to a large extent depends on the accuracy of the rotor circuit time constant determination. Purpose: development of methods for identifying the time constant of the motor rotor circuit and, therefore, clarifying parameters of its model in the control system. Methods: creating an identification system based on replacing the motor rotor circuit with an RL-circuit; simulation of an identification system in a graphical environment of Simulink simulation modeling and optimization of parameters. Results: refinement of parameters of DC motor model used in the indirect assessment of its parameters. The methodology for identifying the rotor time constantinDC motor based on the approximate replacement of this circuit with an RL-circuit.The time constant determination carried out by finding the tangent to the graph of current in this circuit and based on the values of the current measured at a certain time and the steady-state current value. The resulting system allows you to specify the motor parameters necessary for the proper functioning of the control system. The ability to indirect measurement of the electric motor speed with a small error allows you to abandon the use of devices for direct measurement, e.g. encoders. Practical relevance: this identification system improves the control quality of sensorless systems and entire drive reliability.The proposed method can also work to determine the parameters of AC motors (stator circuit). However, in order to simplify the object model we consider DC machine.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):115-128

SELECTING A CLASSIFICATION METHODS AND INCREASING ITS EFFICIENCY IN IDENTIFICATION TASKS ON THE EXAMPLE OF IDENTIFYING FRAUDS IN WALK OUT RETAIL STORES

#### Abstract

The relevance of the task considered in the paper is connected with the use of empirical models and classification methods for the preprocessing and preparation of data, and on their basis, increasing of accuracy and objectivity of decisions made as well as with the consideration of observed systems and tasks, and the use of statistical data. The paper is aimed at considering the identification method selection task to increase its efficiency performance on the base of a specific applied task under continuous data include. For the set task to be handled, the paper investigates the application of machine learning methods on the base of real time-collected statistical data about customer actions in self-service retail shops with a special device for scanning bar codes of goods. The obtained results allow classifying data into two categories (i.e. to identify target states. In the paper, this is the identification of frauds on the base of customer actions. The selected models and the ways to improve their efficiency can be used directly in the areas where staff and clients’ supervision and control in real-time (i.e. based on their e-actions) are of importance. The significance of the study is greatly connected with the outcome according to which classification methods used to consider various tasks show different efficiency levels. In the conducted study is given the method which determines how to build and select the most efficient models for solving binary classification and identification tasks. This process is limited to the series of formal operations, which can be performed by solving any classification task. Efficiency was evaluated with help of ROC curves, and the efficiency of machine learning methods’ performance was measured with help of building models’ ensembles, using cross-validation, special metrics by training models, and resembling.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):129-146

MATHEMATICAL MODELING OF THE NONSTATIONARY THERMAL CONDUCTIVITY OF CABLE LINES LAID IN THE GROUND

#### Abstract

At present, in the production of high-voltage cables with cross-linked polyethylene (XLPE) insulation on the surface of screens, as a rule, fiber-optic temperature sensors are mounted that are used to monitor cable lines in real time during their operation. In this case, the determination of the thermal state of the cable line by the temperature of the optical fiber is possible only using a mathematical model of non-stationary thermal conduction under conditions of changing current load. Research objective: to create a mathematical model for calculating and predicting the temperature of cable strand veins based on data on the environmental parameters, cable line design, and also the temperature in the screens obtained by measurement. Results: research is carried out on the example of a three-phase high-voltage cable line laid in the ground and consisting of three single-core cables with copper conductive conductors with XLPE insulation. Three ways of laying the cable line are considered: in the horizontal plane at a distance in the light equal to the diameter of the cable; in the horizontal plane close; triangle. A two-dimensional mathematical model of non-stationary thermal conductivity is proposed, the numerical implementation of which is carried out in the Ansys Fluent software package. Initially, as a result of solving the problem of stationary thermal conductivity, the nominal current load is determined by the value of the long-term allowable temperature for insulation from cross-linked polyethylene. As an initial condition for solving the problem of non-stationary thermal conduction, the temperature field obtained at a current of 70 % of the nominal value is used. Further, the current in the cable line changes stepwise in the range from 150 % of the nominal to 70 % and vice versa. In the process of numerical studies, the time to reach the maximum temperature to the specified levels is estimated and the change in the temperature difference between the conductive core and the screen is determined. Practical relevance: this mathematical model can be used to assess the temperature conditions of high-voltage cable lines with fiber-optic temperature sensors.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):147-159

SENSORLESS VECTOR CONTROL ASYNCHRONOUS MOTOR WHEN CALCULATING IN A COMPLEX FORM

#### Abstract

The most common method of controlling asynchronous motors is vector control with the installation of sensors directly on the motor. The presence of sensors in the control system increases the risk of equipment failure. The most effective way to improve the quality characteristics of the electric drive,in particular, with vector control, is to approach sensorless methods of controlling an induction motor. Purpose: to develop a method for calculating the speed and position of the rotor of an induction motor with a sensorless vector control with fast programmed calculation time and with a simple implementation of regulation, taking advantage of complex calculations. Methods: the article considers a computer with sensorless control of an induction motor, obtained by solving the system of Park-Gorev equations in complex form. Conducting a simultaneous calculation for two projections of variables using recording in complex form allows you to speed up the calculation speed. Verification of the results was carried out using computer simulation. For these purposes, an asynchronous motor model was built in the MatLab software. Results: a computer assembled on the basis of the solution proposed in this article, with high accuracy (0,5 %) determines the value of the engine speed, has a simple and flexible structure. The solution can be scaled and applied in other versions of the electric drive due to its versatility. Practical relevance: a solution of the Park-Gorev system of equations in a complex form is proposed. A base has been obtained for creating an asynchronous motor control system with an integrated computer. The application of the method considered in the article allows the use of a microprocessor of lower performance and power, which significantly reduces the cost of the hardware of the control system.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):160-176

THE ALGORITHM FOR DETERMINING THE CONDUCTIVE LOW-FREQUENCY ELECTROMAGNETIC INTERFERENCE BY THE COEFFICIENT OF THE NTH HARMONIC COMPONENT OF THE VOLTAGE

#### Abstract

The electric power systems (EPS) of various industrial enterprises for a number of reasons are characterized by low quality of electric energy, in particular, the presence of higher harmonics in the grids, as a result of which conductive low-frequency electromagnetic interference (EMI) occurs, which has a negative effect on electrical equipment. This leads to the problem of the quality of electric energy in the EPS, which negatively affects the electrical equipment. The question of determining the conductive low-frequency EMI by the coefficient of the n-th harmonic component of the voltage within the framework of this problem remains unresolved. Purpose: development of an algorithm for determining the conductive low-frequency EMI by the coefficient of the n-th harmonic component of the voltage, which allows scientifically sound estimation of the electromagnetic environment in electric grids. Methods: the formation of a sequence of actions to determine the quality criterion for the functioning of electric power systems by the coefficient of the n-th harmonic component of the voltage. Results: based on the theory of probability and mathematical statistics, an algorithm has been developed for determining the conductive low-frequency electromagnetic field by the coefficient of the nth harmonic component of the voltage, based on the requirements of the standard GOST 32144-2013. Based on the algorithm, a computer program that allows automated calculation of the parameters of the electromagnetic environment, including the distribution parameters of the coefficient of the n-th harmonic component of the voltage, such as the mean and standard deviation, the probability of the coefficients of the n-th harmonic component of the voltage exceeding the normalized values and the probability of the conductive low-frequency EMI by the coefficient of the n-th harmonic component of the voltage was developed. The program allows you to visualize the data arrays that were obtained during various experimental studies using waveforms and histograms. Practical relevance: the proposed algorithm allows you to generate reliable information about electromagnetic environment in EES and can be used to develop a concept for improving the quality of electric energy, taking into account the analytical and numerical aspects of computer research.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):177-194

STORAGE ELECTROSTATIC ENERGY

#### Abstract

When the distance between electric charges tends to zero, the potential energy of the electrostatic field tends to infinity, which is not good. Possible attempts to save the situation by reasoning about the impossibility of achieving a zero distance due to the finite size of charged objects are unproductive, since it is believed that, for example, electrons and positrons have no sizes. The purpose of the study is to exclude the possibility of developing infinitely large electrostatic energy. The relevance of the work is due to a significant increase in the role of electrostatic energy in connection with the start of mass production of electric vehicles and the need for the development of theoretical support in this regard. Definitions are given. Definition 1. The total stored energy is the energy of a system or an object equal to the maximum work that a system or object can do if it or he is given such an opportunity. Definition 2. The conditional realized stored energy is a part of the total stored energy of a system or object equal to the work that the system or object can do, limited by the condition that excludes the possibility of the system or object performing the maximum work that the system or object can hypothetically perform. Definition 3. Conditional unrealizable stored energy is a part of the total stored energy of a system or object equal to the work that the system or object cannot perform, limited by the condition that excludes the possibility of the system or object performing the maximum work that the system or object can hypothetically perform. A number of theorems are proved, including Theorem 1 - the stored energy is always positive; Theorem 6 - the field energy of a system of two charged spheres, one of which is completely inside the other, is a constant, i.e. independent of the location of the inner sphere.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2020;(33):195-210