Browsing by Author "Koliadenko, Oleksandr"

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    Improving the Efficiency of the Ferroalloy Smelting Process in Electric Arc Furnaces by Improving Control and Management of Technological Modes
    (Український державний університет науки і технологій, ННІ «Дніпровський металургійний інститут», ІВК ≪Системні технології≫, Дніпро, 2025) Nikolenko, Anatolii V.; Nezhurin, Vadym; Kuvaev, Viktor; Verovkin, Oleksandr; Bashko, Volodymyr; Kopysov, Vladyslav; Koliadenko, Oleksandr
    ENG: The article addresses the issues of improving the efficiency of ferroalloy smelting in electric arc furnaces by enhancing the control and management of technological regimes. Recent global trends, such as the increase in the production of high-quality alloy steels and semiconductor products, have led to a sharp rise in the demand for ferroalloys and crystalline silicon. In this context, the intensification of technological processes and the optimization of energy consumption in ferroalloy electric furnaces have become particularly relevant. The ferroalloy smelting process is based on the carbothermic reduction of metals from their oxides, occurring at high temperatures with significant heat absorption. Although the mechanisms and kinetics of the main reduction reactions have been well studied, in industrial conditions, the techno-economic indicators of the process are significantly inferior to those achieved in laboratory settings. The extraction rate of target elements decreases to 75–80%, and the energy consumption exceeds the theoretically necessary amount by 1.5–2 times. Traditional approaches to improving the ferroalloy smelting process through the enhancement of furnace designs and the selection of charge materials with specific physico-chemical properties have largely exhausted their potential. In the context of continuously rising energy costs and deteriorating raw material quality, the urgent problem now lies in implementing fundamentally new approaches to technological process control, focused on detailed monitoring and analysis of the furnace’s current state. The authors justify the necessity of transitioning from the "input-output" control system to a more advanced "input-state-output" principle, which enables real-time analysis of the furnace workspace parameters and prompt influence on the course of the technological process. In particular, significant attention is devoted to the development of methods for analyzing the electrical, thermal, and physico-chemical characteristics of the active zone of the furnace, which determine the main transformation processes of the charge. The paper discusses the design features of electric arc furnaces and describes the structure of the workspace for different types of processes - slag-free and slag-forming. It is shown that the distribution of energy among the zones of the charge, the arc, and the melt has a substantial impact on the techno-economic indicators of production. The peculiarities of arc burning, heat transfer processes, and ionization in the gas cavities of the furnaces are studied. The article highlights the main methods for investigating processes in furnaces: probing, analyzing oscillograms of current and voltage, determining the resistances of the charge and melt, as well as modern methods for assessing power distribution across furnace zones based on measurements of electrical parameters. Special attention is paid to the problem of increasing the accuracy of assessing the parameters of energy processes without interfering with the technological process. The authors emphasize the importance of optimizing the modes of electric power supply and the structural parameters of furnaces to ensure the stability of the bath operation, reduce the dispersion of fluctuations, and minimize losses. Methods for selecting optimal electrode immersion parameters, managing charge regimes, and selecting charge materials considering their electrophysical properties are presented. The article makes a significant contribution to the creation of a scientific basis for improving the efficiency of ferroalloy smelting, which is of particular importance in the context of the modern energy crisis and the growing demands for the quality of metallurgical industry products.
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    Increasing the Reliability of Simulation of Asynchronous Motor Operation Based on an Adaptive Approach
    (Український державний університет науки і технологій, ННІ «Дніпровський металургійний інститут», ІВК ≪Системні технології≫, Дніпро, 2025) Tryputen, Mykola; Kuznetsov, Vitalii V.; Verovkin, Oleksandr; Koliadenko, Oleksandr
    ENG: This research focuses on improving the reliability of simulating the operation of induction motors when solving technical and economic problems related to the selection of protection systems for electric drives operating in industrial power networks with poor power quality. The presence of voltage asymmetry, harmonic distortions, and other power quality issues in workshop networks significantly affects the performance and service life of induction motors, increasing energy losses and maintenance costs. The article proposes a power and economic model that allows conducting computational experiments to determine the optimal solution for improving power supply quality. A key element of the model is the system for generating and controlling linear voltage parameters, which ensures compliance of the simulated signals with their statistical regularities observed in real industrial conditions. The research introduces adaptive algorithms for the continuous and simultaneous assessment of average values, variances, autocorrelation, and cross-correlation functions of voltage harmonics. Mathematical expressions for their correction during the accumulation of information are presented. Structural schemes of control systems for both analog and digital modeling of voltage processes are proposed, allowing for real-time monitoring of the reliability of generated data. The simulation results were verified through statistical hypothesis testing for the average values and variances of the generated voltage harmonics. Experimental studies were carried out in the rolling shop No. 1 of Dneprospetsstal LLC, where significant voltage distortions are caused by the operation of powerful semiconductor converters. The results confirmed the adequacy of the proposed modeling approach and its applicability for making economically sound decisions regarding the choice of technical solutions for voltage quality improvement. This work contributes to the field of energy efficiency in industrial enterprises by providing a methodological basis for the reliable simulation of induction motor operation in the presence of distorted power supply conditions. The proposed approach allows reducing the cost and duration of experimental studies by replacing them with validated computational modeling.
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    Modeling of Electromagnetic Processes in a Nonlinear Circuit of an Electrolyzer for Pulse Deposition of Metal Coatings
    (Український державний університет науки і технологій, ННІ «Дніпровський металургійний інститут», ІВК ≪Системні технології≫, Дніпро, 2025) Bondar, Oleh I.; Siversky, Serhii; Gurin, Yevgen; Koliadenko, Oleksandr; Bashko, Volodymyr; Kopysov, Vladyslav; Pilipenko, Vyacheslav
    ENG: The primary objective of this study is to construct a comprehensive analytical model describing the electromagnetic processes in a nonlinear electrical circuit of an electrolyzer operating under pulsed electrodeposition conditions. Special attention is given to the influence of reversed rectangular voltage pulse parameters on the near-cathode voltage drop, deposition current, and the general electrochemical behavior of the system. The goal is to identify optimal operation modes of the pulse power supply that ensure high-quality metal coatings while minimizing energy consumption and structural defects. Methodology. The research employs the method of variable transformation to develop a set of differential equations describing the dynamic behavior of voltage and current in a nonlinear electrolyzer circuit during pulsed operation. The model accounts for critical circuit components: resistive, capacitive, and inductive elements of the electrolyte, as well as nonlinear conductances reflecting electrochemical properties. Analytical expressions for voltage drop and deposition current are derived for both the forward and reverse pulse intervals. The model includes the influence of electrolyte inductance–an often-neglected factor–which significantly alters the current front shape and ultimately affects deposition kinetics and coating characteristics. Numerical simulations are performed to validate the analytical solutions. Results. Closed-form analytical expressions were obtained for the time-dependent near-cathode voltage drop and deposition current under pulsed conditions. It was shown that the electrolyte inductance leads to a rounding of the current front, influencing both the amplitude and stability of the electrochemical reactions. A parametric analysis identified that the optimal pulse duty cycle lies in the range of τ/T ≈ 0.73 to 0.78. Within this interval, the maximum near-cathode voltage drop does not exceed 0.6 V, while the peak voltage and total current remain within safe technological limits (up to 13 V and 150 A, respectively). The average partial discharge current at the cathode remains stable at approximately 70 A, ensuring consistent deposition rates. Scientific novelty. This work introduces a novel analytical approach to modeling pulsed electrodeposition that, for the first time, includes the effect of electrolyte inductance. Unlike existing models relying heavily on numerical simulations, the proposed model allows for direct computation of key process parameters. It enables the derivation of precise criteria for determining the optimal ranges of input pulse parameters–both in amplitude and duration–necessary to avoid the formation of crystalline defects and to achieve uniform, high-quality coatings. These innovations significantly advance the theoretical understanding of pulsed electrochemical processes. Practical significance. The developed model provides a valuable tool for industries that utilize electrochemical metal deposition, including microelectronics, galvanics, mechanical engineering, and power systems. It offers a foundation for designing advanced pulse power supplies with optimized operation modes and supports the development of automated control systems for deposition processes. Furthermore, the model can aid in adapting laboratory results for industrial implementation, improving coating quality, process efficiency, and operational reliability.