Факультет електромеханіки та електрометалургії (ДМетІ) <br> Дніпровський металургійний інститут (ДМетІ)

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ENG: Faculty of Electromechanics and Electrometallurgy
Dnipro Metallurgical Institute

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Adaptation of a Predicate Model in Control Problems of Nonstationary Static Objects
(Український державний університет науки і технологій, ННІ «Дніпровський металургійний інститут», ІВК ≪Системні технології≫, Дніпро, 2025) Tryputen, Mykola; Kuznetsov, Vitalii V.; Verovkin, Oleksandr; Ivliev, Vitalii
ENG: When controlling static objects at the optimization level, pattern recognition methods are used that allow partitioning the factor space into elementary subdomains in the form of n-dimensional hyperparallelepipeds. One of the main elements of the control structure for this approach to control is the adaptation algorithm, that makes it possible to refine the description of a static object under nonstationarity conditions. Repeated use of the adaptation algorithm to refine the model leads to an unjustified complication of its logical structure and the accumulation of information that has lost its relevance. The paper proposes a method for minimizing the description of images of technological situations, that makes it possible to overcome the indicated disadvantages. The method is based on the property of invariance of the number of parameters defining the hyperparallelepiped to the size of the described area in the factor space. This made it possible to identify significant boundary sub-areas in the description of the image of technological situations and, by their subsequent combination in the direction of the feature axes, to select a description with a minimum number of sub-areas. When performing these operations, “outdated” information is removed and the logical structure of a static control object is simplified as much as possible. The paper shows the possibility of implementing an algorithm for minimizing the description of images on the basis of α-algebra, that makes it possible to integrate its control structures using relational data models. The effectiveness of the proposed algorithm is confirmed by computational experiments in the control of the process of lump crushing for the conditions of a mining and processing plant.
Adaptation of a Predicate Model in Control Problems of Nonstationary Static Objects
(Український державний університет науки і технологій, ННІ ≪Дніпровський металургійний інститут≫, ІВК ≪Системні технології≫, Дніпро, 2025) Tryputen, Mykola; Kuznetsov, Vitalii V.; Yvanova Lyudmyla Kh.
ENG: When controlling static objects at the optimization level, pattern recognition methods are used that allow partitioning the factor space into elementary subdomains in the form of n-dimensional hyperparallelepipeds. One of the main elements of the control structure for this approach to control is the adaptation algorithm, that makes it possible to refine the description of a static object under nonstationarity conditions. Repeated use of the adaptation algorithm to refine the model leads to an unjustified complication of its logical structure and the accumulation of information that has lost its relevance. The paper proposes a method for minimizing the description of images of technological situations, that makes it possible to overcome the indicated disadvantages. The method is based on the property of invariance of the number of parameters defining the hyperparallelepiped to the size of the described area in the factor space. This made it possible to identify significant boundary sub-areas in the description of the image of technological situations and, by their subsequent combination in the direction of the feature axes, to select a description with a minimum number of sub-areas. When performing these operations, “outdated” information is removed and the logical structure of a static control object is simplified as much as possible. The paper shows the possibility of implementing an algorithm for minimizing the description of images on the basis of α-algebra, that makes it possible to integrate its control structures using relational data models. The effectiveness of the proposed algorithm is confirmed by computational experiments in the control of the process of lump crushing for the conditions of a mining and processing plant.
Advanced Space Vector Modulation with “Fractional” Power Cells
(Elsevier B.V., 2025) Busher, Victor; Shestaka, Anatoliy; Melnikova, Lubov; Kuznetsov, Vitaliy V.; Mykhailenko, Oleksii; Kovalenko, Viktor; Kutyk, Viktor; Osadchyi, Dmytro; Osypenko, Iryna O.; Abdel Gawad, Samer
ENG: The paper develops a model and studies various operating modes of a 5-phase multi-level cascade inverter as part of high-voltage powerful variable-frequency drives (VFD) with the most typical fan load for this type of electric drives. The aim of the work is to test the efficiency of the balanced spatial-vector pulse-width modulation method in a multi-phase high-voltage multi-level inverter in emergency modes by simulating the electric drive in the MATLAB/SIMULINK/Simscape Electrical environment. The paper studies the features of using the balanced spatial-vector pulse-width modulation method in a five-phase frequency converter in normal and emergency modes and, especially, the differences from a three-phase inverter with a similar control principle. The model with a 5-phase synchronous motor from the MATLAB ac8_example.slx database is taken as a basis, which allows us to consider the simulation results reliable. The rules for calculating phase voltages in normal and emergency modes are formulated and the corresponding blocks of the inverter control system model are prepared - a block for calculating basic vectors and a block of spatial vector pulse-width modulation (PWM). The output signals of this block are used for further processing in the modules for controlling power cells with 2- or 3-level PWM. Such a model for a 5-phase electric drive has been built for the first time, which is a scientific novelty of the work. Calculations of transient processes showed the absence of any oscillations, shocks when the system switches from normal to emergency mode and vice versa. That is, the proposed method of balanced spatial vector modulation preserves the symmetry of electromagnetic fields in the engine when individual H-bridges are damaged. It is shown that in normal mode, a 5-phase inverter using the spatial vector modulation method allows increasing the utilization factor of voltage sources by 23.1%. When individual power cells in phases fail, the utilization factor may decrease, but in any case it remains greater than 1. The method ensures compensation for emergency damage even in the event of a short circuit of one or two inverter phases. This significantly increases the service life of the electric drive, which is especially important in critical mechanisms and technological processes, where such complex inverters are actually used. The study found that when using the proposed method in a 5-phase VFD, unlike a 3-phase one, the current balance in the load is disrupted, which leads to increased heating of individual phases of both the motor and the power section of the inverter. The second point of scientific novelty of the work is that in order to reduce this negative effect, it is proposed to improve the algorithm for calculating the output coordinates of the regulator by using the so-called “fractional” power cells with a voltage that is not a multiple of their rated voltage. This leads to a smooth change in phase shifts and asymmetry when individual H-bridges and even one or two phases are damaged. This, in turn, reduces the current imbalance and the corresponding overheating from 2...3 to 12...15%, which gives confidence in the efficiency of using this improvement. It is also important to note that such a change in the control algorithm does not require any changes in the circuit and does not increase the requirements for the computing power of the processors used.
Alumophosphate Binders: Synthesis, Phase composition, Thermal Stability and Application in Foundry Production
(Elsevier B.V., Netherlands, 2025) Petryk, Ivan; Liutyi, Rostyslav V.; Osypenko, Irina O.; Myslyvchenko, Olexander; Byba, Ievgen; Lukianenko, Ivan
ENG: Organic binders currently used in the foundry industry are highly toxic. During the pouring of casting molds, many volatile organic compounds are released, the vast majority of which are environmentally harmful. The development of alumophosphate binders will have a positive impact on the environment. The article gives the results of the study of aluminum phosphate binders, which are the result of the chemical reaction of orthophosphoric acid with powdered aluminosilicates. The subjects of the research are the phase and chemical composition, the dynamics of thermal transformations of the binders, as well as the properties of core mixtures for the production of foundry cores. It was found experimentally that as a result of the chemical reaction of powdered pyrophyllite Al2(OH)2[Si4O10] and disten-sillimanite Al2O[SiO4] with orthophosphoric acid after heating to 300 оС, strong and thermally stable binders are formed, which are crystalline and amorphous aluminum orthophosphates. These phases ensure binding of the quartz refractory filler and therefore high strength. Synthesized binders can be used in refractories or core mixtures for foundry production. X-ray phase and differential thermogravimetric analyzes were used to determine the structure and properties of binders. The compositional planning of the experiment with appropriate data processing was applied to determine the working composition of the mixture for foundry cores. The structure of aluminum phosphate binders, which were obtained using refractory fillers common in foundry production, was investigated for the first time. The circumstances for the formation of crystalline phases were analyzed for the first time. It was established that as a result of the reaction of orthophosphoric acid and disten-sillimanite, the larger specific amount of aluminum orthophosphate and the smaller amount of residual quartz is formed, compared to the reaction of acid with pyrophyllite. This ensures the higher strength of the core mixture, which is formed from the binders in which orthophosphoric acid and disten-sillimanite are used. Taking into account the mass ratios for the whole realization of the chemical reaction of the formation of the aluminum phosphate binders, the core mixture on the basis of quartz sand, orthophosphoric acid and disten-sillimanite was developed, which hardens after heating to 300 оС and has a compressive strength of at least 2.0 MPa.
Analysis and Design of the Interval Optimal Electromechanical Systems
(ScientificWorld-NetAkhatAV, Karlsruhe, Germany, 2025) Voliansky, Roman; Kuznetsov, Vitaliy V.; Metelenko, Natalia; Kovalenko, Viktor; Spirintsev, Dmytro V.; Babyak, Mykola O.; Tryputen, Mykola; Tkalenko, Oleksandr; Halushko, Dmytro
ENG: The monograph has been prepared as part of comprehensive scientific research aimed at improving energy efficiency, digitalization, and the development of intelligent control systems. The materials presented reflect the results of many years of interdisciplinary research carried out with the participation of specialists from various scientific schools and universities. They provide a holistic understanding of modern trends in electric drive system control and form a scientific and practical basis for introducing innovative solutions in industry and transport. The discussed concepts of optimization, robust control, and the integration of renewable energy sources are closely linked to the transition to sustainable energy, automation of production processes, and infrastructure digitalization. Special attention is given to interaction with international research programs, which allows the use of advanced experience from Germany, Japan, the USA, and other countries in the field of digital twins, the industrial Internet of Things (Industrial IoT), andcyber-physical control systems.
Analysis of Operational Characteristics of SRM in Emergency Modes of the Converter Unit
(IEEE, 2022) Vlasenko, Vladimir; Tytiuk, Valerii; Kuznetsov, Vitalii V.; Kuntush, Yelena; Chornyi, Oleksii; Busher, Victor
ENG: The paper analyzes the issues of maintaining the operability of a switched reluctance motor (SRM) in various emergency situations. The researches were carried out using simulation modeling in the Matlab environment, the developed model was used for both normal and emergency operation modes. A series of dynamic tests of the motor torque has been carried out, and the values of the electromagnetic torque pulsation coefficient have been calculated. The possibility of maintaining the operability of SRM in the event of various emergency situations in the phases of the motor has been proved. The static mechanical characteristics of the motor are built and the calculation of the droop of the mechanical characteristics for possible emergency modes is performed. © 2022 IEEE.
Analysis of the Neutral Grounding Modes Influence on the Reliability Characteristics of Local Systems with Renewable Energy Sources
(Polskie Towarzystwo Diagnostyki Technicznej, Warszawa, 2021) Ostapchuk, Oleksandr; Kruczek, Włodzimierz; Kuznetsov, Valeriy; Kuznetsov, Vitaliy; Tsyplenkov, Dmytro
ENG: When comparing the performance indicators of electrical networks with different types of neutral grounding, along with the fulfilment of the requirement to ensure reliability of power supply to consumers, serious attention is drawn to the main network parameters influencing the performance of power supply systems. Analysis of research and its results, reported above, on the influence of the neutral ground of power networks on the reliability and electrical safety conditions of the power supply systems as a whole, on the damage of distribution networks and electrical equipment as well as on the working capacity of relay protection devices, provides an opportunity to estimate each specific operation mode of the neutral and to develop recommendations aimed at strengthening the positive indicators of the corresponding modes. Other things being equal, reliability of power supply to electrical receivers or reliability of distribution networks is mainly determined by the damage to network elements and the performance of relay protection devices. The degree of influence of these factors on the reliability of distribution networks depends on the neutral mode, which in turn determines the level of overvoltages and the nature of transient processes at ground failure.
Assessing Criteria for Casting and Deformation Suitability of Metals and Alloys
(Dnipro University of Technology, Dnipro, 2025) Kimstach, Tetiana V.; Uzlov, Kostiantyn I.; Bilyi, Oleksandr P.; Mazorchuk, Volodymyr F.; Repyakh, Serhii I.
ENG: Purpose. Based on existing criteria for predicting the suitability of metals and their alloys for manufacturing products from them by deformation or casting analysis develop a set of dimensionless parametric criteria and their quantitative scales. Their using will allow increasing the predicting accuracy of metals and alloys for their processing by pressure or casting suitability and feasibility. Methodology. The work uses phenomenological approach to systematic analysis results of metals and alloys mechanical and individual casting properties interpreting under uncertainty conditions, drawing on literature reference data, expert evaluation data and the authors’ own research results. The authors’ own data have been obtained experimentally using standard methods for mechanical properties determining and due to original authors’ method for technical purity metals and alloys based on them cast samples values of their absolutely hindered linear shrinkage determination during casting. Findings. The authors first proposed parametric dimensionless criteria and scales to them (criteria groups). Their application allows one, through such groups combinations, to assess suitability of any alloy or metal for its use possibility for products manufacturing by casting and/or pressure processing. Originality. For the first time dimensionless parametric criteria have been developed and proposed for use at initial stages of new alloys or technologies elaboration for products from them manufacturing as well as their quantitative scales for preliminary assessment (prognosis) of alloys processing feasibility by pressure or casting, regardless of their type and method. Practical value. Developed criteria and their quantitative scales using will allow alloys developers and specialized enterprises employees to save time and expenses both for alloy elaboration and for its implementation into production.
Assessment of Human-Operator’s Influence on Technical and Economic Indicators of the Excavator Production Cycle
(Dnipro University of Technology, Dnipro, 2025) Tytiuk, Valerii; Mrachkovskyi, D.; Chornyi, Oleksii; Kuznetsov, Vitalii V.; Tryputen, Mykola; Sivyakova, Galina
ENG: Purpose. Determining the influence of the parameters of the human-operator transfer function on the duration of the technological operation and the cyclic energy consumption of the electromechanical system of a straight shovel excavator equipped with electric drives of various types in order to further improve the human-machine control system of open-pit excavators by compensating for the inertia and nonlinearity of the human-operator characteristics. Methodology. Mathematical modeling of the human-machine control system of an excavator equipped with electric drives of various types, taking into account the dynamic characteristics of the human-operator, establishing regression dependencies of technical and economic indicators of the excavator on the parameters of the equivalent transfer function of the human-operator using design of experiments. Findings. The mathematical models of closed-loop control systems for the position of the bucket of a “straight shovel” excavator with an electric drive according to the Leonard system and a thyristor converter-motor electric drive have been implemented, which differ in that their structure takes into account the nonlinearity and inertia of the human operator and its influence on the performance of the human-machine system. Using the methods of the theory of experiment planning, we obtained regression dependences of the duration of the technological cycle and cycle energy consumption on the values of the time constant and the delay constant, which characterize the current state of the human-operator. The obtained regression models made it possible to evaluate the importance of the influence of various psycho-physiological factors of the human-operator on the technical and economic indicators of the excavator production cycle, which can serve as the basis for further optimization of the operation of mining excavators. Originality. For the first time, mathematical models of the electromechanical system of an excavator according to the “straight shovel” scheme are proposed, including models of electric drives of the main mechanisms, a model of the mechanical part of the excavator and a model of a human-operator, which made it possible to increase the accuracy of determining the energy consumption of the excavator and the time of the operating cycle. The regression models of technical and economic indicators of the excavator production cycle on the delay and inertia of the human-operator were obtained. It was found that the more influential factor is the transportation delay. Practical value. Mathematical models of an excavator with an electric drive based on the generator-motor system and an electric drive based on the thyristor converter-motor-motor system have been developed, including a model of the mechanical part of the excavator and a model of a human-operator. Regression models of the dependence of the duration of the excavator production cycle and its energy consumption on the delay and inertia of the human-operator are obtained. The proposed implementation of the human-machine excavator control system creates prerequisites for further increasing the level of automation of mining excavators.
Automatic Compensation of the Mill RolL Eccentricity in Terms of Limited Speed of Hydraulic Compression Devices
(Dnipro University of Technology, Dnipro, 2025) Boyko, O.; Kuvaiev, Victor; Potap, Oleg; Potap, M.; Rybalchenko, Maria O.
ENG: Purpose. To reduce deviation of vertical dimension (thickness) of rolled products from the specified value by enhancing the accuracy and shortening the setup time of an eccentricity compensation subsystem of mill rolls based on substantiation of an eccentricity compensation method. This method is based on an active search algorithm to determine the actual eccentricity parameters in real time, taking into account the actual response time of hydraulic compression devices (HCD) and investigating its effectiveness through simulation computer modelling. Methodology. The research was based on the analytical determination of the frequency characteristics of the AGC system in sheet metal rolling, considering the actual response time of HCD of a rolling mill as well as a comprehensive model of a rolling process in a quarto mill with rolling movement and an automatic thickness control system (ATCS) that compensates for eccentricity. The study was conducted by comparing the results of computer simulation modelling of the improved ATCS, whose algorithm took into account the HCD response time, with the performance indicators of the previous system, which did not consider this factor. Findings. It has been established that under the AGC thickness control conditions, the measured amplitude of a variable component of thickness does not match the amplitude of eccentricity due to the finite response time of HCD. The frequency characteristics of the AGC system have been determined analytically, taking into account the actual response time of HPD in a rolling mill. An improved procedure for determining the actual eccentricity amplitude in real time has been substantiated, which involves a temporary reduction in the HCD speed within the initial rolling section. A structure for an automated control system has been proposed for practical implementation of this procedure. It has been demonstrated that the proposed solutions allow for a threefold reduction in thickness variations caused by eccentricity compared to the corresponding performance indicators of the known eccentricity compensation systems with the AGC thickness control. Originality. The influence of the HCD response time on the accuracy of AGC thickness control systems for rolled products has been established. An approximate linear relationship has been identified between the ratio of the amplitude of thickness fluctuations caused by eccentricity and the amplitude of roll gap fluctuations relative to the roll speed and HCD response time under the AGC algorithm thickness control conditions. The improved procedure for determining the actual eccentricity amplitude in real time has been substantiated. Practical value. The effectiveness is substantiated of implementing an improved active search algorithm for determining the eccentricity parameters of mill rolls under the limited HCD response conditions in real time. This approach allows for a threefold reduction in the sheet thickness variability caused by roll eccentricity compared to the performance indicators of the known AGC thickness control systems, thereby ensuring the production of high-precision rolled products in Ukrainian sheet rolling mills.
Coefficient of Local Loss of Mechanical Energy of the Flow for a Mixture of Charge Materials
(Dnipro University of Technology, 2021) Selegej, Andriy Mikolayovich; Ivaschenko, Valeriy; Golovko, Vjacheslav Iljich; Kiriya, R.; Kvasova, Luydmila Sergijvna
ENG: Purpose. To determine the dependence of the coefficient of local losses of mechanical energy of flow of a twocomponent mixture of charge material on its depth, content of components, and average equivalent diameter of particles in the case of their freedispersed motion. Methodology. The value of the coefficient of local losses of mechanical energy was determined by the value of the hydraulic resistance of the fluid during its movement in open channels and pipes. In this paper, methods were used of comparative analysis, mathematical modeling and forecasting of dynamic processes in the flow of granular material. findings. Based on the results of theoretical studies, a mathematical model was obtained, the use of which allows calculating the coefficient of local losses of mechanical energy for the flow of a twocomponent mixture of charge materials with agglomerate particle sizes from 15 to 50 mm, pellets from 6 to 12 mm, coke from 10 to 60 mm. The developed model with satisfactory accuracy makes it possible to evaluate the movement of the charge from the indicated materials along the paths of the charging devices of blast furnaces at a speed in the range from 1.5 to 20 m/s and to determine the trajectories of the mixture of charge materials on the top with an accuracy of 0.2 m. It is noted that the calculation of the above coefficient by the known techniques is not accurate enough, which is associated with the uncertainty in the choice of a single average equivalent diameter of the particles of the two component charge. Comparative analysis of the developed model with the known models and experimental data indicates that the accuracy of calculating the dynamic parameters of a twocomponent flow of charge materials using the developed model increases by 5–10 % in comparison with calculations using the previously known models. Originality. For the first time, regularities of changes in the coefficient of internal mechanical losses of a twocomponent flow of charge materials from its depth, content of components, average equivalent particle diameters when moving along the paths of charging devices of blast furnaces have been established. practical value. Mathematical dependencies have been developed and can be used to determine the technological parameters of the charge of a modern blast furnace with different characteristics of the granulometry of the charge and the ratios of its components. This will increase the accuracy of predicting the course of the process under consideration, the degree of automation of the control systems for the technological process of the charge supply of blast furnaces, will make it possible to use expensive charge materials more efficiently, reduce energy consumption and reduce the harmful impact on the environment.
Communicative Competence Development in Teaching Professional Discourse in Educational Establishment
(MECS Press, 2021) Kyrpychenko, Olena; Pushchyna, Iryna; Kichuk, Yaroslav; Shevchenko, Nataliia; Luchaninova, Olga; Koval, Viktor
ENG: The article is devoted to the question of communicative competence formation, represented in all spheres of professional application in higher education and states that the degree of its formation depends on a person's approach to behave in different social situations. This study examines the essence and structure of communicative competence, as well as the system of its formation while teaching a foreign language to higher education students of economics. Evaluation of the characteristics of developing communicative competence when working with economic texts is carried out as the main communicative unit on the example of the use of specific material in speech. The methodology of the formation of communicative competence among future economists is theoretically determined and experimentally tested through interaction with economic texts in English for professional purposes (49 students aged 17–20 years participated in the research). Analysis of linguistic, psychological, psycholinguistic and methodological bases of communicative competence formation, questionnaires of students and survey results gave grounds for the development of experimental methods of these competences formation by future economists in the process of studying modern foreign language. The interactive methods of learning from economic texts were developed under a new concept of teaching foreign language for the formation of communicative competence and introduced in experimental groups of learners. The data indicated a significant increase in intermediate and high levels of future economists’ communicative competences formation in groups with interactive classes.
Complex of Mathematical Models and Methods to Calculate Pressure Effect on Sulfide Distribution in Steel
(Хмельницький національний університет, Україна, 2021) Selivyorstova, Tetjana V.; Selivyorstov, Vadim Yu.; Kuznecov, Vitaliy V.
ENG: Primary objective is to develop computational method to analyze digital pictures of sulfide prints, helping obtain qualitative image characteristics, and to formulate mathematical model of the distribution of sulphide inclusions to determine specific features of the pressure effect on the macrostructure formation of carbon steel castings flooded into the uncooled mold. The research was carried out using images of sulfide prints of templates cut of steel cylindrical castings; L500 steel was applied. The castings result from industrial tests of a method of gas-dynamic effect on the fusion in the foundry forms under the conditions of a casthouse of Dnipropetrovsk aggregate plant PJSC. Digital pictures of sulfide prints, obtained in terms of the increased rate of gas pressure and maximum pressure, were binarized; defective fra gments were removed; and zo ning took place. The developed computational method has been applied for fragments of images, representing different zones; data arrays have been received containing sizes and amounts of inclusions in the fragment. The developed computational method to analyze digital images of sulfide prints has been implemented. ASImprints software support has helped obtain qualitative characteristics of images; namely, distribution of amount of the certain-size sulfide inclusions. The computational method to analyze digital images of sulfide prints has made it possible to study the set of patterns of sulfide prints. The dependences have been obtained, describing specific features of sulfide inclusion distribution while varying gas-dynamic pressure method in terms of fusion in the casting form. It has been demonstrated that the distribution describes effectively the power-series distribution to compare with the exponential one. Mathematical model of the power -series distribution parameter dependence upon pressure has been developed. Deviation of the distribution parameters in terms of the experimental values and the model values has been evaluated. The research demonstrates the ways to apply an algorithm of simple recursive casting for quantitative analysis of digital images of sulfide prints. Use of ASImprints, being software implementation of the computational method to analyze digital images of sulfide prints making it possible to obtain qualitative characteristics of images, has helped identify that the increased pressure within a casting-device for gas injection system results in the increased specific amount of inclusions and the decreased specific zone of sulfide inclusions respectively. It has been defined that exponential function describes reliably the nature of sulfide inclusion distribution in the digital image of sulfide print. The research has demonstrated that fragments of a sulfide print, belonging to one zone, are statistically homogeneous. Thus, it is possible to analyze quantitively digital image zone of a sulfide print on its fragment. Mathematical model of dependence of sulfide inclusion distribution in carbon-steel castings in terms of gas-dynamic effect on fusion solidifying in a mold has been developed. The model may be applied to predict sulfide inclusion distribution within the selected zones of cross section of the cylindrical castings solidifying in the uncooled mold in terms of the preset mode of gas-dynamic effect.
Complex Solid-Phase Reduction in a Blast Furnace of Self-Healing Pellets of Cold Agglomeration Containing By-Product Carbon Materials of Metallurgical Production
(Ukrainian State University of Science and Technologies, Dnipro, 2025) Vaniukov, Anton A.; Ivashchenko, Valerii P.; Ivanova, Liudmyla Kh.; Kovalov, M.; Tsybulia, Ye.
ENG: The reactions of direct and indirect reduction occurring during the heat treatment of self reducing pellets (SRP) have been studied. In this investigation Blast furnace (BF) sludge which contains particles of coke, has been included in the SRP blend as a source of solid reductant. In the SRP as a part ot the blast furnace burden occur the reactions simultaneously: inside of SRP-direct reduction by Csolid; gasification of carbon and indirect reduction by CO; and outside of SRP-indirect reduction of iron bearing oxides by reducing gas coming from the hearth of blast furnace through the column of charged materials. The experiments was performed continuously from the start temperature (~200 ˚C) to the experimental temperature (500 ˚C; 700 ˚C; 900 ˚C; 1100 ˚C) in argon free environment. Upon reaching the desired temperature argon was replaced by hydrogen during 30 minutes. After that the reduced probe of SRP was cooled in argon. The objective of the present work is to research a quantitate ratio of degree direct reduction inside of SRP and degree of indirect reduction outside of SRP on the top of the blast furnace.
Construction of a Kinetic Equation of Carbon Removal for Controlling Steel Melting in the Metallurgical System "Cupola Furnace – Small Converter"
(TECHNOLOGY CENTER PC, Kharkiv, 2025) Makarenko, Dmytro M.; Selivorstova, Tetiana V.; Dotsenko, Yuriy V.; Osypenko, Iryna O.; Dzevochko, Oleksandr M.; Pereverzieva, Alevtyna M.; Dzevochko, Alona I.
ENG: The object of research in the paper is the process of steelmaking in a small converter, which works in tandem with a cupola furnace. The existing problem is that the control of the process of obtaining steel in an oxygen converter is complicated by the need to determine in real time the current chemical composition of the melt, in particular carbon. This is due to the fact that the rate of carbon removal is too high, as a result of which the process of carbon removal is transient. Therefore, it is too difficult to implement regulation based on feedback on continuous measurement. The presence of the specified problem requires solutions related to the possibilities of developing or improving software control of the process. It is shown that in certain sections of the process within each time section of oxygen purging of the melt in the converter, the kinetic curve has a linear form with a constant coefficient value in front of the inlet mine. But the value of the initial coefficient for each equation that describes the process within its limits changes. This allows to state that in case of a change in the initial condition, the kinetic curves shift relative to each other in parallel. On this basis, a system of equations has been constructed that describes the process of carbon removal in a small oxygen converter that receives liquid iron from a cupola furnace. It has been shown that to use the obtained system of equations, it is necessary to know the initial carbon content in the melt discharged from the cupola furnace, and it depends on the method of oxygen supply to the cupola furnace. Based on the modeling of this process in two variants – using a “sharp blow” and supplying oxygen to the air blown into the tuyeres, a nomogram has been constructed. It allows to determine the initial carbon content for the practical use of the obtained system of equations. Using the obtained system makes it possible to determine the time after which oxygen cutoff should be made. This will allow to decide to implement software control of the melt blowing process in the converter. The presented study will be useful for machine-building enterprises that have foundry shops in their structure, where cast iron is smelted for the manufacture of castings.
Control of Drum Shear Electric Drive Using Self-Learning Artificial Neural Networks
(MDPI, Basel, Switzerland, 2025) Batyrbek, Alibek; Kuznetsov, Valeriy; Kuznetsov, Vitalii V.; Rojek, Artur; Kovalenko, Viktor; Tkalenko, Oleksandr; Tytiuk, Valerii; Krasovskyi, Pavlo
ENG: The objective of this work was to study the possibility of upgrading the control system of the drum shear mechanism by using neural network PI controllers to improve the efficiency of the sheet-metal cutting process. The developed detailed model of the mechanism, including a dual DC electric drive with three subordinate control loops for the voltage of the thyristor converter, current and speed of the motors, a 6-mass kinematic system with viscoelastic connections as well as a model of the metal cutting process, made it possible to uncover that the interaction of electric drives with the mechanical part leads to significant speed fluctuations during the cutting process, which worsens the quality of the sheet-metal edge. A modified system of current and speed controllers with built-in three-layer fitting neural networks as nonlinear components of proportional-integral channels is proposed. An algorithm for the fast learning of neural controllers using the gradient descent method in each cycle of calculating the controller signal is also proposed. The developed neuro-regulators make it possible to reduce the amplitude of speed fluctuations during the cutting process by four times, ensuring the effective damping of oscillations and reducing the duration of transient processes to 0.1 s.
Coordinated Control of the Composition of 01yut Steel and Deformation Processing Modes to Achieve Specified Mechanical Properties
(National Metallurgical Academy of Ukraine, Ukrainian State University of Science and Technologies, Dnipro, 2024) Velychko, A. G.; Kamkin, V. Yu.; Proidak, Yurii S.
ENG: Purpose: to investigate the influence of the chemical composition of steel on the output from the chipboard and to establish rational parameters of deoxidation and deformation to ensure the specified values of mechanical properties. Methods: physicochemical modeling, thermodynamic calculations, experimental studies. Results: the carbon content and the degree of oxidation of the semi-finished product from the electric furnace for further vacuum treatment to obtain low-carbon steel were determined. With an increase in the oxygen flow rate supplied to the chipboard and exceeding the value required for the stoichiometry of fuel combustion reactions, the oxidation of the semi-finished product increases. To avoid the formation of calcium silicates, it is necessary to have an active oxygen content below 2.5 ppm, which is ensured by the residual content of dissolved aluminum in steel of 0.025-0.027%. Scientific novelty: The use of complex deoxidizers in steel production allows using the synergistic effect of the joint deoxidizing action of deoxidizing elements. The use of the methodology of physicochemical modeling made it possible to effectively solve the problem of predicting the properties of steel. To study the influence of modifier elements, as well as the main alloying components, a number of parameters characterizing the state of the alloy as a whole (Zу, d) were calculated. Based on information on the significant influence of the chemical composition of the steel on its properties, a database of 150 compositions was prepared to determine the optimal composition of ultra-low-carbon steels of the 01ЮТ, 01ЮТА type by the method of physicochemical modeling. Based on the calculations, the concentrations of elements for steels of the 01ЮТ and 01ЮТА grades were selected.
Corrosion Resistance of Reinforced Layers of 15х11МФ Steel Steam Turbine Blades
(Національний науковий центр «Харкiвський фiзико-технiчний інститут», 2021) Hlushkova, D. B.; Bahrov, V. A.; Hrinchenko, O. D.; Hnatiuk, A. A.; Kalinina, N. E.; Kalinin, V. T.
ENG: The reliability of the vane apparatus of steam turbines largely determines the operation of the turbine as a whole. The results of scientific research indicate that the surface operation of the blades in the wet-steam flow is caused by a combination of corrosion and drip erosion. The presence of chemical elements and compounds in the working fluid intensifies the process of blade wear. The pH value of the working environment, which can fluctuate significantly during operation, has a significant effect on the wear characteristics. The influence of methods of strengthening the leading edges of steam turbine blades made of steel is analyzed 15H11MF on corrosion resistance. Corrosion tests of blade samples were carried out, the inlet edges of which were strengthened in three ways: high current amplification, electrospark alloying with T15K6 alloy, electrospark alloying with steel 15H11MF. According to the results of the tests, the layer strengthened by hardening by high-frequency currents has the lowest corrosion rate, the layer strengthened by electrospark alloying with T15K6 hard alloy has the highest. The corrosion rate of the layer reinforced by electrospark alloying of steel 15H11MF is 2.1 less than that of the layer reinforced with T15K6 alloy.
Creative Methods as an Obligatory Component of the Technical Specialists Education in the Post-Industrial Era
(Faculty of Organization and Management at the Silesian University of Technology, Silesian Voivodeship, Poland, 2024) Molokanova, Valentyna M.; Petrenko, Vitaliy O.; Kuznetsov, Valeriy; Kuznetsov, Vitalii V.; Krol, Agnieszka; Kacprzak, Marzena; Wielewska, Izabela; Wyrzykowska, Barbara
ENG: Purpose: The article's objective is formalization of the model, the main stages and creative methods of training technical specialists, the definition of features and directions for further education development in the post-industrial era. The article is aimed at revealing the nature of creativity, highlighting the essence of the functions of methods of creative activity and their importance for students of technical specialties. Design/methodology/approach: The work uses critical analysis of scientific and methodological sources, system and convergent analysis methods, generalization and systematization of practical experience. The method of convergent generalization made it possible to identify key indicators of the model of creative competencies. The conceptual model of creative competence was developed based on the results of cooperation on the frame of master's programs for the project managers training. For the practical part of research, a qualitative method was used (participant observation, individual interview, tests). Findings: The need to train technical specialists in the methods of creative search using modern technologies, which allows to achieve the effects of the intellectual potential development for the individual, the state and society, is justified. An experiment on training project managers of two Ukrainian institutes in creative technologies proved the feasibility of implementing such training. Based on the calculation of the creative competencies’ development of the first- and second-year study technical specialists, the need to add a mandatory creative component to educational programs has been determined. Implications/Recommendations: To assess the quality of training, a methodology for assessing the level of competence has been applied. This made it possible to identify a low level of some competencies and, at the stage of improving the curriculum, plan the necessary corrective actions for the development of weak components of competencies. Since project-oriented learning is used, the model is similar to the model of the classical project life cycle and will be especially useful in the implementation of innovative projects in production. The article presents a framework for teaching students creative competence, which can be used by other educational institutions. Originality/value: The review of literary sources proved that so far very little attention has been paid to the development of creative competencies in students of technical specialties, although these competencies will be the competitive advantage of a person in the competition with artificial intelligence. The model of creative competencies for the technical specialists training is presented, which is divided into four areas, which in turn are divided into four components. These areas relate to the sampling and systematization of knowledge; adaptation to user requirements; awareness and dissemination of hidden knowledge; transition to the active use of knowledge.
Design of a Circuit-Field Model of a Closed-Loop Electric Drive System Based on a Switched Reluctance Motor
(Dniprovsky State Technical University, Kamianske, Ukraine, 2024) Kachura, Oleksii V.; Kolychev, Serhii V.; Suhal, Yevhen O.; Kuznetsov, Vitaliy V.; Nikolenko, Anatolii V.
ENG: The distribution of switched reluctance motors (SRM) is due to their specific properties: high reliability due to the absence of sliding contacts, precise positioning, wide range of regulation. These properties allow the use of SRM in various adjustable electric drives in conjunction with semiconductor control systems. The complexity of the study such systems is a correct representation of both, the control system and the motor, taking into account their mutual influence and energy exchange. In addition, as a rule, SRM have a rather specific design, which limits the use of classical methods for their calculation and causes the use of numerical methods. The paper presents a mathematical model of a closed loop drive system on the rotor position and speed, based on the SRM. As a result of the unification of the SRM field model constructed on the basis of the Laplace and Poisson equations and the circuit model of the control system, a circuit-field mathematical model is obtained. The mathematical model takes into account the design features of the motor and allows to explore a drive system in dynamic modes of operation. An algorithm for switching power inverter keys for four phases of the SRM is developed. From the obtained values of magnetic induction and tension tensors the electromagnetic moment of the motor calculated. Electromagnetic and electromechanical parameters of the serial SRM-57-100-4 in the start-up mode obtained for the proposed model.
Determination of Bronze БрА7К2О1,5Мц0,3 Crystallization Interval Limit Values and Phase Transformations
(Dnipro University of Technology, Dnipro, 2025) Kimstach, Tetiana V.; Uzlov, Kostiantyn I.; Bilyi, Oleksandr P.; Solonenko, Lyudmila I.; Repyakh, Serhii I.
ENG: Phase transformations temperatures, crystallization intervals, etc. are any alloy’s fundamental parameters. Alloys’ casting, technological and operational properties are related to them. Nevertheless, unlike two-component bronzes, such requirements for multi-component structural, non-magnetic, corrosion-resistant bronze БрА7К2О1,5Мц0,3 are absent. Purpose. For Cu-Al-Si-Sn-Mn system bronzes, crystallization intervals quantitative values (liquidus and solidus temperatures, crystallization interval size and solid phase relative share in it) have been established. БрА7К2О1,5Мц0,3 bronze’s alloying components’ synergistic and selective influence on its crystallization interval and relative fluidity indicators changing has been determined. Methodology. Well-known methods and research techniques, including thermography, differential thermal analysis, spectral chemical analysis, images analysis digital method have been used in this work. Bronzes fluidity has been assessed using spiral test. Bronze’s alloying elements’ synergistic and selective influences on its characteristics have been determined using chemical elements ratio in it (KR criterion) and experimental data results processing by Excel computer program. Findings. In bronze БрА7К2О1,5Мц0,3 with KR criterion value rising from 0.35 to 0.84, there increase liquidus, solidus temperatures and crystallization interval from 32 to 49 °C. Bronze’s alloying elements’ (Al, Si, Sn, Mn) synergistic and selective influences on its crystallization interval limit values have been determined. It has been established that conditionally-veritable fluidities of БрА7К3О1,5Мц0,3 and БрА9Ж3Л bronzes are practically the same. For Cu-Al-Si-Sn-Mn system bronzes with KR = 0.35‒2.07, solid phase relative volume fraction (φSP) in crystallization temperature range is 60‒63 %. Originality. For the first time, limiting values and phase transformations for БрА7К2О1,5Мц0,3 bronze’s crystallization interval and alloying elements synergistic and selective influence on these indicators have been determined. Practical value. Based on БрА7К2О1,5Мц0,3 bronze’s chemical composition selected, mathematical models have been proposed for its liquidus and solidus temperatures calculating and for transition from dependences of solid phase t(φSP) volume fraction in crystallization temperature range to temperatures’ absolute values t(φSP). Their use will allow increasing the indicators of foundry and technological parameters accuracy forecasting.
Determination of Conditions for Preventing Chemical Wear of Induction Furnace Lining in the "Cupola Furnace – Induction Furnace" Duplex Process
(TECHNOLOGY CENTER PC, Kharkiv, 2025) Nikolaev, Denis A.; Selivorstov, Vadim Yu.; Dotsenko, Yuriy V.; Osypenko, Iryna O.; Kuznetsow, Eugene V.
ENG: The object of research is the melting of cast iron in the “cupola furnace – induction furnace” duplex process. The need to study such a duplex process is dictated by the condition of ensuring the required quality of cast iron in the event that a low-quality or uncontrolled charge is used. This condition cannot be met if the induction furnace is used as the only melting unit. But the problem is that in the process of induction melting of cast iron, in particular at the stage of overheating and holding the melt, a crucible reaction may begin, which leads to chemical wear of the lining. The need to reduce the carbon content in the melt discharged from the cupola furnace requires an increase in temperatures, which creates risks for the onset of a crucible reaction. Based on statistical calculations of cupola melting parameters, it was found that in the melt discharged from the cupola furnace into the induction furnace, the average carbon content is C = 3.47% with a standard deviation SC = 0.14%, and the average silicon content is Si = 2.05% with a standard deviation SSi = 0.21%. At the same time, with a probability of 96%, the carbon content is C = (3.33–3.75)%, and the silicon content corresponds to the range Si = (1.84–2.46)% with a probability of 98%. It was found that the equilibrium constant is in the range (0.15–0.21) with a probability of 97.8% at an average temperature T = 1355°C with a standard deviation of temperature ST = 6°C. With such melt parameters, which are supplied to the induction furnace, the risks of the onset of a crucible reaction do not arise. It was determined that even at temperature regimes sufficient to remove FeO, the risk of the onset of a crucible reaction is minimal. In order to ensure conditions that prevent the onset of a crucible reaction, the following recommendations should be followed for the content of carbon and silicon in high-temperature melting when the temperature is in the range T > 1480°C: C > 0.3% and Si < 0.3%. The results of the study can be used in the melting sections of foundries equipped with cupola furnaces and induction furnaces.
Determining the Optimal Composition of Low-Basicity Slags Using Pegmatite for Electromelting Processes
(TECHNOLOGY CENTER PC, Kharkiv, 2026) Proidak, Yurii S.; Gorobets, Anton P.; Zhadanos, Oleksandr V.; Rybalchenko, Mariia O.
ENG: This study focuses on the process of slag formation and its performance during steelmaking using carbon charge, when remelting alloyed scrap in electric steelmaking units, and in secondary metallurgy units. One of the relevant issues is the use of alternative materials, such as alkali aluminosilicates, capable of replacing conventional slag components without compromising the quality of the slag. This study reports scientifically proven conditions for replacing fluorspar in the composition of slags used in remelting technologies and secondary metallurgy with domestic mineral raw materials – pegmatites, which contain up to 10–15% of the total alkali metal oxides Na2O and K2O. The effect of Na2O and K2O on the rheological characteristics of the slag melt in the CaO-SiO2+(Na2O, K2O) system has been confirmed. A series of experimental meltings was carried out to establish the slag-forming regime in a ladle-furnace when fluorspar in the solid slag-forming mixture is completely replaced with pegmatites. A comparative analysis of the compositions of refining slags for the current industrial technology and the experimental technology has been performed. A significant increase in slag fluidity and a desulfurization level of the metal comparable to that of the current technology were established, despite a decrease in slag basicity to 1,8–2,0, which is consistent with the requirements of remelting technologies. Chemical analysis of the metal and slag compositions was conducted for the experimental meltings at the stages of semi-product melting and steel treatment in the ladle furnace. The metal from the experimental meltings fully met the requirements of the normative and technical documentation. Thus, this work provides a theoretical justification for an innovative secondary-metallurgy technology using alkali aluminosilicate pegmatite as a part of slag forming mixtures. The metal quality indicators in terms of sulfur content confirm the effectiveness of the devised technology with partial or complete replacement of fluorspar with pegmatite during remelting or secondary steelmaking.
Determining the Thermally-Stressed State of Motor-Driven Bowls for Transporting Liquid Slag
(РС ТЕСHNOLOGY СЕNTЕR, Kharkiv, 2024) Povorotnii, Viktor V.; Shcherbyna, Iryna V.; Zdanevych, Serhiі V.; Diachenko, Nina K.; Kimstach, Tetiana V.; Solonenko, Lyudmila I.; Usenko, Ruslan V.
ENG: Slag bowls were chosen as the object of research, as important components of blast furnace, steelmaking, and ferroalloy shops of metallurgical enterprises. The main problem of operation of any slag trucks is their limited durability and frequent destruction of slag bowls. The reason for these problems is changes in the shape of the bowls during operation, manifested in the formation of narrowing places in the area of the support ring – for rail-mounted bowls, destruction of supporting pins – for rail-mounted slag trucks, or cracks in the walls. Those defects appear as a result of cyclic thermal effects of liquid slag on the bowl. Based on the results of computer simulation, it was established that the main role in the destruction of the support pins of motor-driven slag bowls belongs to temperature changes. The temperature stresses arising in the bowl are localized in the area of the slag mirror (200–250 MPa for 25L steel, 280–350 MPa for 30HML steel). The results provide grounds for improving the presented slag bowl to reduce temperature stresses in its walls and structures of the supporting trunnions. The results reported here are explained by the fact that with uneven heating of elastic bodies, temperature stresses appear, which, under certain configurations of temperature loads, lead to the destruction of structures. The findings from these studies are recommended to be used at enterprises for the design and manufacture of slag bowls, as information on the localization of dangerous places of the structure. In addition, the data presented here could be useful for metallurgical enterprises for detailed technical diagnosis of bowls in their dangerous places.
Development of a Digital Twin of a DC Motor Using NARX Artificial Neural Networks
(MDPI, Basel, Switzerland, 2025) Busher, Victor; Kuznetsov, Valeriy; Ciekanowski, Zbigniew; Rojek, Artur; Grudniewski, Tomasz; Druzhinina, Natalya; Kuznetsov, Vitalii V.; Tryputen, Mykola; Hubskyi, Petro V.; Batyrbek, Alibek
ENG: This study presents the development process of a digital twin for a complex dynamic object using Artificial Neural Networks. A separately excited DC motor is considered as an example, which, despite its well-known electromechanical properties, remains a non-trivial object for neural network modeling. It is shown that describing the motor using a generalized neural network with various configurations does not yield satisfactory results. The optimal solution was based on a separation into two distinct nonlinear autoregressive with exogenous inputs (NARX) artificial neural networks with cross-connections for the two main machine variables: one for modeling the armature current with exogenous inputs of voltage and armature speed, and another for modeling the angular speed with inputs of voltage and armature current. Both neural networks are characterized by a relatively small number of neurons in the hidden layer and a time delay of no more than 3 time steps. This solution, consistent with the physical understanding of the motor as an object where electromagnetic energy is converted into thermal and mechanical energy (and vice versa), allows the model to be calibrated for the ideal no-load mode and subsequently account for the influence of torque loads of various natures and changes in the control object parameters over a wide range. The study demonstrates that even for modeling an object such as a DC electric drive with cascaded control, reducing errors at the boundaries of the known operating range requires generating test signals covering approximately 120% of the nominal speed range and 250–400% of the nominal current. Analysis of various test signals revealed that training with a sequence of step changes and linear variations across the entire operating range of armature current and speed provides higher accuracy compared to training with random or uniform signals. Furthermore, to ensure the neural network model’s functionality under varying load torque, a mechanical load observer was developed, and a model architecture incorporating an additional input for disturbance was proposed. The SEDCM_NARX_LOAD neural network model demonstrates a theoretically justified response to load application, although dynamic and static errors arise. In the experiment, the current error was 7.4%, and the speed error was 0.5%. The practical significance of the research lies in the potential use of the proposed model for simulating dynamic and static operational modes of electromechanical systems, tuning controllers, and testing control strategies without employing a physical motor.
Development of a Method of Calculating the Temperature of a Survey Assembly When Preparing a Train Dispatch
(Львовский политехнический национальный университет, Львів, 2020) Ustymenko, Dmytro V.; Kuznetsov, Vitaliy; Marenych, Oksana L.; Kovzel, Maksim; Mukha, Andrii M.; Sinkevych, Oleksiy; Tryputen, Mykola; Al Said Ahmad, Mohammad Ahmad Diab
ENG: The features of the thermal state of the current collection unit «contact wire – contact insert of the current collector» in the conditions of preparation of electric rolling stock for the journey are considered. As part of the study, a methodology has been developed for estimating the heating temperature of the power sliding contact zone in the conditions of train preparation for journey. Application of the method will help to reduce the number of «burnouts» of the contact wire due to the exact selection of the heating/cooling time of the train for a certain heating/conditioning current when preparing the electric rolling stock for the journey. It was established that the cause of the «burns» of the contact wire in the parking lots when preparing the train dispatch is the excess of the permissible temperature of the power sliding contact as a result of the prolonged action of the heating/conditioning current. The standard approach for determining the duration of heating is based on the average values of the loads on the system and therefore does not take into account some factors, for example, the state of the contact wire, the state of the contact insert of the current collector, the number of cars in the train, and so on. The proposed technique is based on the classical theory of electrical contact and the theory of heating a homogeneous body, which makes it possible to accurately assess the thermal state of the power sliding contact and convenient enough for use in operating conditions. The results of the work are of practical value, since the technology of preparing a train for dispatch can be supplemented by calculating the contact temperature «contact wire element – contact insert element» in accordance with the proposed methodology. This will allow for a specific train in specific conditions to apply a set of measures to prevent «burnout» of the contact wire in the event of a possible temperature exceeding the permissible value.
Development of Mathematical Models of Energy Conversion Processes in an Induction Motor Supplied from an Autonomous Induction Generator with Parametric non-Symmetry
(НВП ПП «Технологічний Центр», Харьків, 2021) Chenchevoi, Volodymyr; Kuznetsov, Valeriy; Kuznetsov, Vitalii V.; Zachepa, Iurii; Chencheva, Olga; Chornyi, Oleksii; Kovzel, Maksim; Kovalenko, Viktor; Babyak, Mykola O.; Levchenko, Serhii
ENG: The paper presents studies of the system “induction generator-induction motor” with parametric asymmetry on a mathematical model to determine the quality of generated electricity in load operating modes. A mathematical model of the “induction generator-induction motor” system has been developed taking into account losses in steel and parametric asymmetry. The analysis of the transient characteristics of an induction generator when a motor load is connected in symmetrical and asymmetrical modes of operation is carried out. The results of changes in the main characteristics of an induction motor at various degrees of parametric asymmetry in the generator are presented. The quality of the generated electricity was analyzed based on the calculations of the unbalance coefficients for each of the operating modes. The assessment of the thermal state in steady-state conditions was carried out using an equivalent thermal equivalent circuit. Thermal transients were investigated when starting an induction motor from an autonomous energy source based on an induction generator. On a thermal mathematical model, the study of the effect of the output voltage asymmetry on the heating of the connected induction motor was carried out. It is shown that the asymmetry of the output voltage of an induction generator reaches 3–10 % and causes overheating of the windings in excess of the permissible values. A regression model has been developed for studying the operating conditions of an induction motor when powered by an induction generator with an asymmetry of the stator windings. The use of the obtained equations will make it possible to determine the most rational combination of factors affecting the heating of the stator windings of induction machines, in which they will not overheat above the maximum permissible temperature values of the corresponding insulation classes.
Development of the System of Initial Excitation of the Autonomous Induction Generator
(Springer, Singapore, 2022) Chenchevoi, Volodymyr; Kuznetsov, Valeriy; Zachepa, Iurii; Chornyi, Oleksii; Chencheva, Olga; Kuznetsov, Vitaliy V.; Yatsiuk, Rostyslav; Luhova, Olha
ENG: The article defines the conditions of self-excitation of an inductive generator with capacitor excitation as part of an autonomous power source. Recommendations for the design of an autonomous power source based on an asynchronous machine in terms of the implementation of self-excitation conditions and optimal operating modes are formulated. A simulation model of an autonomous inductive generator and a solar battery for the analysis of transient, static and dynamic modes of operation has been developed. The conducted theoretical studies of capacitive self-excitation of inductive machines have created a good basis for solving problems related to the practical use of autonomous sources based on an inductive generator.
Distribution of Chromium in Transition Layer of Bimetallic Castings
(Latvia University of Life Sciences and Technologies, Jelgava, 2025) Aftandiliants, Yevhenii; Gnyloskurenko, Svyatoslav; Meniailo, Helena V.; Khrychikov, Valerii Ye.
ENG: The constantly increasing requirements for machine components and mechanisms operating under conditions of impact and abrasive wear determine promising use of bimetallic cast parts. Their quality significantly depends on both the technological factors of manufacture and the properties of the transition layer between the base and the working layer. The aim of the work was to study the influence of the casting mass, the ratio of the mass of the steel base and the working layer of cast iron and the difference in the chromium content in the layers, the pouring temperature of steel and cast iron on the quality of the casting. Research was carried out on bimetallic castings of steel 25L – cast iron 300Kh12G5 and steel 70GL – cast iron ChKh22. The mathematical model of the influence of selected parameters on the width of the chromium transition zone from cast iron to steel and the average rate of chromium concentration change in the transition layer was developed. It was established that the most effective influence on this zone and the rate of chromium change is exerted by the mass and temperature of the steel base, the contribution of which is 67.7% and 60.2%, respectively. It was shown that the width of this zone decreases with increasing difference in the chromium content in the matrix of the working layer and the base and expands with increasing the pouring temperature and mass of steel and cast iron. It was determined that increasing the pouring temperature and the mass of the steel base and the working layer leads to a decrease and the chromium content in the matrix of the working layer and the base to an increase in the average rate of the change of the chromium concentration in the transition layer. These data are useful for optimizing the technology of obtaining high-quality bimetallic castings.
Dynamic Modeling of Induction Motor Performance under Power Quality Disturbances
(Український державний університет науки і технологій, ННІ «Дніпровський металургійний інститут», ІВК ≪Системні технології≫, Дніпро, 2026) Kuznetsov, Vitalii V.; Nikolenko, Anatolii V.; Stopkin, Vasyl V.; Martyntsev, Viacheslav; Tuhushy, Roman; Teslenko, Ivan
ENG: The paper presents a dynamic electromagnetic model of a three-phase squirrel-cage asynchronous motor developed to simulate its operation under real power quality disturbances. The relevance of this work is driven by the increasing impact of electromagnetic compatibility issues and energy losses in industrial systems exposed to voltage asymmetry and harmonic distortion–conditions typical for networks with nonlinear loads such as welding equipment, arc furnaces, and frequency converters. Traditional motor models, which assume ideal supply conditions, are not sufficient for accurately predicting performance degradation under such disturbances. To address this limitation, the proposed model is based on space-time complexes and an extended form of the Park–Gorev equations. A key feature of the model is the inclusion of magnetic core saturation, represented through a polynomial dependence of mutual inductance on magnetizing current, enabling more realistic simulation under high-load and unbalanced conditions. The model was tested on an MTKH 112-6 motor (5.3 kW) under two scenarios: ideal sinusoidal voltage and distorted asymmetric supply with harmonics up to the 10th order. The results showed that voltage distortion leads to increased losses in the stator (from 491.3 W to 498.3 W) and rotor (from 652.2 W to 661.5 W), a decrease in efficiency (from 81.4% to 81.2%), and a significant drop in power factor (from 0.98 to 0.90). Additionally, distorted current waveforms and torque pulsations confirmed higher electromagnetic stress. The model demonstrated strong agreement with experimental data (RMSE < 4%), confirming its reliability for applications in diagnostics, predictive maintenance, digital twins, and simulation environments. Unlike traditional Fourier-based approaches, the use of space-time complexes enables comprehensive modeling of both steady-state and transient processes without explicit harmonic decomposition. This research contributes to the development of energy-efficient and intelligent industrial systems. Future work will focus on incorporating stochastic elements to account for dynamic variations in power quality, supporting predictive control and advanced automation within Industry 4.0.
Efficient Algorithms for Parallelizing Tridiagonal Systems of Equations
(НМетАУ, Дніпро, 2021) Shvachych, Gennady Grygorovych; Vozna, Nataliіa; Ivashchenko, Olena V.; Bilyi, Oleksandr P.; Moroz, Dmytro
ENG: The article is devoted to the development of the maximal parallel forms of mathematical models with a tridiagonal structure. The example of solving the Dirichlet and Neumann problems by the method of straight lines and the sweep method for the heat equation illustrates the direct fundamental features of constructing parallel algorithms. It is noted that the study of the heat and mass transfer processes is run through their numerical modeling based on modern computer technology. It is shown that with the multiprocessor computing systems’ development, there disappear the problems of increasing their peak performance. On the other hand, building such systems, as a rule, requires standard network technologies, mass-produced processors, and free software. The noted circumstances aim at solving the so-called big problems. It should be borne in mind that the classical approach to solving the tridiagonal structure models based on multiprocessor computing systems is far more time-consuming compared to single-processor computing facilities. That is explained by the recurrence relations that make the basis of classical methods. Therefore, the proposed studies are relevant and aim at the distributed algorithms development for solving applied problems. The proposed research aims to construct the maximal parallel forms of mathematical models with a tridiagonal structure. The paper proposes the schemes to implement parallelization algorithms for applied problems and their mapping to parallel computing systems. Parallelization of tridiagonal mathematical models by the method of straight lines and the sweeping method allows designing absolutely stable algorithms with the maximum parallel form and, therefore, the minimum possible time for their implementation on parallel computing devices. It is noteworthy that in the proposed algorithms, the computational errors of the input data are separated from the round-off errors inherent in a PC. The proposed approach can be used in various branches of metallurgical, thermal physics, economics, and ecology problems in the metallurgical industry.
Electrotechnical Materials
(RS Global, Warsaw, Poland, 2021) Tsyplenkov, Dmytro; Nikolenko, Anatolii V.; Kolb, Andrii; Grebeniuk, Andrii; Kuznetsov, Vitalii V.; Babyak, Mykola O.; Kovalenko, Viktor
ENG: The regularities of processes and phenomena that occur in dielectric, conductive, semiconductor and magnetic materials as part of electrical and electronic devices under the influence of energy of electric, magnetic and thermal fields are considered. The main feature of the textbook is a detailed structuring of educational material, focusing largely on the distance form of learning, as well as demonstration of the close relationship of the properties of various electrical materials and the basics of electrical engineering on specific examples. The manual is intended for students of specialties: 141 - "Electrical Energetics, Electrical Engineering and Electromechanics" and 275 - "Transport technologies", as well as for students of other specialties of higher education, which are related to the study of disciplines of electrical engineering and electronic computer science.
Enhancing Power Quality within the Context of Industrial Enterprises: Strategies for Improvement
(ScientificWorld-NetAkhatAV, Karlsruhe, Germany, 2023) Tryputen, Mykola; Kuznetsov, Vitaliy V.; Nikolenko, Anatoliy V.
ENG: The paper analyzes negative impact of poor-quality electricity on the performance of electrical installations. Particular attention is paid to the ways to improve power quality under the conditions of industrial enterprises. Use of “individual” LC-filters to protect extra important electric drives; use of “group” devices to compensate negative effect of noisy electricity at a workshop level (power active rectifiers are meant with their potential integration into the available converters for the controlled electric drives); and to inhibit voltage distortions within the areas of their origination (i.e. the mains protection against the root cause) are possible means to solve the problems.
Estimating the Probability of the Emergency Operation of the Quarry Electric Locomotive Traction Electric Drive
(RS Global Sp. z O.O., Poland, 2021) Artemenko, Artem; Chornyi, Oleksii; Sydorenko, Valeriy; Serhiienko, Serhii; Zachepa, Yurii; Kuznetsov, Vitaliy; Kuznetsova, Alisa
ENG: The paper deals with the problem of the assessment of the functionality of the multi-motor direct current traction electric drive of the quarry electric locomotive. The problem of the failure of electric drive motors because of extremely unsatisfactory state of the rail tracks and the wear of wheel pairs is analyzed. Taking into account the number of the existing repaired electric motors the probability of fitting up the traction electric drive with the electric motors with the widest electrical parameters variety is determined.
Forecasting the Power Generation of a Solar Power Plant Taking into Account the Statistical Characteristics of Meteorological Conditions
(MDPI, Basel, Switzerland, 2025) Kuznetsov, Vitalii V.; Kuznetsov, Valeriy; Ciekanowski, Zbigniew; Druzhinin, Valeriy; Tytiuk, Valerii; Rojek, Artur; Grudniewski, Tomasz; Kovalenko, Viktor
ENG: The integration of solar generation into national energy balances is associated with a wide range of technical, economic, and organizational challenges, the solution of which requires the adoption of innovative strategies for energy system management. The inherent variability of electricity production, driven by fluctuating climatic conditions, complicates system balancing processes and necessitates the reservation of capacities from conventional energy sources to ensure reliability. Under modern market conditions, the pricing of generated electricity is commonly based on day-ahead forecasts of day energy yield, which significantly affects the economic performance of solar power plants. Consequently, achieving high accuracy in day-ahead electricity production forecasting is a critical and highly relevant task. To address this challenge, a physico-statistical model has been developed, in which the analytical approximation of daily electricity generation is represented as a function of a random variable—cloud cover—modeled by a β-distribution. Analytical expressions were derived for calculating the mathematical expectation and variance of daily electricity generation as functions of the β-distribution parameters of cloudiness. The analytical approximation of daily generation deviates from the exact value, obtained through hourly integration, by an average of 3.9%. The relative forecasting error of electricity production, when using the mathematical expectation of cloudiness compared to the analytical approximation of daily generation, reaches 15.2%. The proposed forecasting method, based on a β-parametric cloudiness model, enhances the accuracy of day-ahead production forecasts, improves the economic efficiency of solar power plants, and contributes to strengthening the stability and reliability of power systems with a substantial share of solar generation.
The Formation of Collective Subjects’ Small Social Groups in the Information age (Problem of Identity)
(Universidade Estadual do Sudoeste da Bahia (Uesb), Brasil, 2021) Palahuta, Vadym I.; Beskaravainyi, Stanislav S.
ENG: Purpose. Studying the impact of artificial intelligence (AI) technology on society, which leads to the formation of fundamentally new social groups. The greatest diversity and freedom of development will be allocated to small social groups that directly interact with AI. It is necessary to formulate the foundations of a model that will describe their genesis and self-maintenance. Methodology. Philosophical methods of hermeneutics, comparative method, structuralism and poststructuralism, social constructivism are used. Findings. To create a working model, further research is needed in two directions. First, to improve the categorical apparatus for describing a collective subject based on human-machine interaction. Secondly, the analysis of social groups in which, on the one hand, the human psyche loses its integrity, on the other hand, these groups remain stable and efficient. Originality. Thanks to AI, small social groups will have access to tools for organizing activities that previously had only larger social structures. Increasing subjectivity can lead both to an increase in their role in societies and to the fact that such groups can relatively quickly isolate themselves or marginalize. The threat is identified: the individual may be unable to give up their behavioral-cognitive and emotional identification with the group. The behavior of an individual will be determined both by the influence of AI of a small social group and by the influence of state structures. Practical value. Development of methods for small groups in modern social conditions using artificial intelligence.
The Generalized Chaotic System in the Hyper-Complex Form and Its Transformations
(Springer, Cham, 2022) Voliansky, Roman; Volianska, Nina; Kuznetsov, Vitaliy V.; Tryputen, Mykola; Kuznetsova, Alisa; Tryputen, Maksym
ENG: The paper deals with the development of the mathematical backgrounds to design the novel chaotic systems by transforming existent ones. These backgrounds are based on using well-known shift, rotation, and scale transformations and we offer using hyper-complex numbers to simplify these transformations and represent the transformed chaotic system by using the one 1st order ordinary differential equation. In such form all well known, newly discovered and unknown chaotic systems have the similar mathematical models that are differs only by used nonlinear function of hyper complex variable in the right hand expression. That is why the consideration chaotic system dynamic in the hyper-complex domain allows us to simplify initial system definition as well without applying any transformations. This fact simplifies mathematical definition of chaotic systems and their modeling and simulation. The right-hand expression of the transformed equation in this case are defined as the combination of transformation hyper-complex numbers and source system nonlinearity which is given in the hyper-complex domain. We offer to use variable transformation factors to improve the performance of the considered chaotic system. Since the above-mentioned variable factors can be produced by other chaotic systems, we suggest designing the novel chaotic system by combining existed ones with the linear transformations. As an example, we consider the transformation of the well-known Lorenz system and show the differences between the source system and target one.
Graphitizing Modification of the Axial Zone of Cast Iron Rolling Rolls in the Liquidus-Solidus Temperature Range
(Dnipro University of Technology, Dnipro, Ukraine, 2023) Khrychikov, Valerii E.; Meniailo, Helena V.; Semenov, O. D.; Aftandiliants, Y. G.; Gnyloskurenko, S. V.
ENG: Purpose. To develop a method for calculating a process of graphitizing modification of unsolidificated liquid-solid zone to reduce transcrystallinity of the macrostructure and the amount of cementite in the center of castings. Methodology. The duration of solidification of the castings was determined by the kinetic curves of liquidus, solidus and pouring boundary in coordinates of relative thickness of the solidified metal layer – the parametric criterion of Gulyaev. Findings. A methodology for the process of modification of the axial zone of rolling was developed, the mass and time of adding aluminum were determined according to the amount of liquid-solid phase that remains after the solidification of the working layer. On the example of a rolling roll weighing 1115 kg, 0.488 kg of aluminum was added into liquid-solid zone after the working layer solidified. Movement of aluminum to the front of crystallization is provided by centrifugal forces and adding of aluminum along the height of the roll. Originality. For the first time, the kinetic curves of liquidus, solidus and pouring boundary have been plotted in coordinates of the relative thickness of the solidified metal layer x/R and τ/R2 – the parametric criterion of Gulyaev for rolled cast iron alloys cooled in chill-sand molds of various sizes. A methodology was developed for calculating the process of aluminum modification of the axial zone of rolling rolls after solidification of the working layer in the barrel which was set at the pouring boundary. The amount of aluminum depends on the remains of the liquid-solid phase. Practical value. Graphitizing modification reduces transcrystallinity of the macrostructure and the amount of cementite in the axial zone of castings. A promising direction for further development is the development of new methods for manufacturing castings due to physical and mechanical effects on the two-phase zone, deoxidation and alloying of the central zones of castings.
Heat Balance of Billets during Hot Extrusion of Nickel Alloy Pipes
(Ukrainian State University of Science and Technologies, Dnipro, 2026) Medvedev, M. I.; Bobukh, Oleksandr S.; Kuzmina, O. M.; Krasiuk, A. D.; Ivanova, Liudmyla Kh.
ENG: Among the problems encountered in the production of nickel-based alloy pipes by hot extrusion sleeves on horizontal hydraulic presses, one of the main ones is the high level of product surface defects. To reduce rejects on this basis, it is important to understand the changes in the temperature field of the pipe billet throughout the entire technological process, since this factor is the key to the formation of surface defects in such pipes. The purpose of the work is to establish the regularities of temperature changes in nickel alloy pipe billets at the main stages of pipe production, which are made by extrusion on presses with a force of 16.0 MN and 31.5 MN with the use of glass lubricants. Methodology. The work was performed based on the results of a systematic analysis of the main technological stages of the actual process of producing hot-extruded pipes made of nickel alloy 602CA on presses with a force of 16.0 MN and 31.5 MN. The selected production stages include: transporting the billet (liner) from the induction heater to the glass-filled table, applying glass-filled material to the billet surface, transporting the billet with glass-filled material to the press, holding the billet in a container before extrusion, and extrusion in the container. The calculation of the stepwise temperature loss by the billet was performed using known and own empirical equations obtained from the results of thermography of the billets. The chemical composition of the billets was determined using an Elvax plus spectrometer. The temperature of the outer surface of the workpiece was measured using chromium-aluminium thermocouples complete with an electronic potentiometer. Results. It was found that the total change in the temperature of the sleeves during the cooling process during auxiliary operations on presses with a force of 16.0 MN and 31.5 MN at the same initial heating temperature of the workpieces is inversely proportional to their wall thickness. At the same time, this dependence is almost linear in the range of 40...120 mm wall thickness of the sleeves and 1050...1250 °C heating temperatures of the workpiece. Scientific novelty. For the first time, a methodology for calculating the temperature of the sleeves at the main stages of their preparation for the extrusion process has been developed. Practical utility. The use of the developed methodology for calculating the temperature of the liner allows for a reasonable choice of glass lubricant for the initial technological operations of extrusion on presses with a force of 16.0 MN and 31.5 MN using glass lubricant, which in turn contributes to improving the surface quality of pressed pipes, reducing the level of pipe rejects and reducing the volume of their the volume of their further mechanical processing.
High-Performance Multiprocessor Systems
(Український державний університет науки і технологій, ННІ «Інститут промислових та бізнес технологій», 2022) Ivashchenko, Valery Petrovych; Shvachych, Gennady Grygorovych; Ivashchenko, Olena Valerievna; Sushko, Larisa Fedorovna
ENG: The paper is devoted to the modeling of high-performance multiprocessor architecture for data processing systems used to solve problems with an expandable calculations' area. The proposed system is characterized by high reliability and high energy efficiency. The system contains a separate reconfigurable network for the exchange of data between computing nodes, managed switches. The system also provides network booting nodes and redundancy mechanism of key components.