Перегляд за Автор "Chumack, Vadim"

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  • Ескіз
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    Design of a multilink system for calculating high-frequency processes in electric machines with mesh windings
    (TECHNOLOGY CENTER PC, 2023-09-20) Chumack, Vadim; Kovalenko, Mykhailo; Tymoshchuk, Oksana; Stulishenko, Andrii; Ihnatiuk, Yevhen
    This study considers the design of a multi-link high-frequency circuit for calculating defective and defect-free insulation of mesh windings in order to increase the operational reliability of general-purpose electric machines. The object of research is mesh windings of electric machines. The problem to be solved: increasing the operational reliability of electric machines with general-purpose mesh windings by analyzing and modeling defects. The research results make it possible to model defects for the analysis of the state of insulation of electric machines with mesh windings. Special attention in the research was paid to induction motors with a worn-out resource, in particular, 4A80A4 UZ engine. The analysis includes phase-to-body capacitance, winding inductance, eddy current impedance, and winding impedance. Under the WN mode, a decrease in the impedance of the winding section from 3 % to the short-circuit mode was simulated; accordingly, the resonance frequencies for each case of 3 % were determined – 73990 Hz, short-circuit – 74450 Hz, as well as the corresponding input impedances 8938.7 and 8082.5. The corresponding voltage resonances and current resonances were also determined. Appropriate results were also given for the WG scheme. The results reported here relate to the design of the scheme and the research on the defects of the mesh winding. This contributes to the analysis of the state of insulation of mesh windings. The numerical data (resonant frequencies and input impedances) allow a better understanding of the behavior of windings in different states and degrees of defects. Given the research findings, it is possible to better identify and analyze potential defects in mesh windings, which in turn contributes to increasing the reliability of electric machines. The results of this study could be used in the field of diagnosis, service, and maintenance of electric machines with mesh windings.
  • Ескіз
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    Research of high-frequency remagnetization model in laminated magnetic cores of electromechanical and electromagnetic energy converters
    (TECHNOLOGY CENTER PC, 2023-10-15) Chumack, Vadim; Tymoshchuk, Oksana; Kovalenko, Mykhailo; Bazenov, Volodymyr; Ihnatiuk, Yevhen; Stulishenko, Andrii
    The object of research in the work is charged magnetic conductors of electric machines and transformers. Laminated magnetic wire together with windings are important active parts of electric machines that participate in electromechanical energy conversion. The reliability of the entire machine is mainly determined by the actual condition of the inter-sheet insulation. Violation of the insulation causes parasitic eddy current circuits, which increases the specific losses, and also significantly affects the additional heating of the magnet wire and winding. The normative method for determining the quality of the charged core is the assessment of specific losses at a frequency of 50 Hz and an induction of 1 T, which should not exceed 2.5–4 W/kg. To determine local damage to the core, methods of local heating and fixation of overheating sites are used, which should not exceed 45 °C compared to the main part of the magnetic core. In the work, a two-dimensional field mathematical model of a charged magnetic circuit is developed. This makes it possible to carry out electromagnetic calculations in a near-real magnetic conductor, taking into account the variability of magnetic permeability, hysteresis, and the interaction of currents in adjacent plates of the magnetic conductor with each other, the so-called "proximity effect". On the basis of the developed models, graphs of current distribution and distribution of magnetic induction in one, two and three sheets were obtained. The resulting graphs show how the effect of current displacement increases with increasing frequency, where at a frequency of 100 kHz the magnetic induction density in the middle of the sheet goes to zero. The results of the research confirm the correctness of the model development in comparison with the classical calculation models also given, which allows them to be used for further research of high-frequency processes in charged magnetic circuits of electric machines.
  • Ескіз
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    Voltage stabilization of a controlled autonomous magnetoelectric generator with a magnetic shunt and permanent magnet excitation
    (Eastern-European Journal of Enterprise Technologies, 2021) Chumack, Vadim; Bazenov, Volodymyr; Tymoshchuk, Oksana; Kovalenko, Mykhailo; Tsyvinskyi, Serhii; Kovalenko, Iryna; Tkachuk, Ihor
    The paper presents the results of testing and research of the characteristics of a controlled autonomous magnetoelectric synchronous generator with a magnetic shunt. Structurally, the studied generator is a modified asynchronous machine in which the rotor is made with permanent magnets and an additional system in the form of a magnetic shunt. By adjusting the winding current of the magnetic shunt, the output voltage of the generator is regulated. The following characteristics were investigated: the no-load characteristic during operation with permanent magnets and when the winding current of the magnetic shunt changes with forward and reverse polarity. Also, the external char acteristic for active and active-inductive loads; the control characteristic when the load current changes at a constant generator voltage. Analysis of the obtained characteristics makes it possible to determine the limits of regulation of the external characteristic, which is ≈40 % relative to the main magnetic flux. The obtained regulation depth allows maintaining the stability of the external characteristic for power factors not exceeding 0.9, which is the usual passport value for autonomous power plants based on synchronous generators. Comparison of the data of research conducted on the experimental setup shows sufficient convergence for engineering and practical tasks. The maximum quantitative difference is 9.3 %, which suggests the adequacy of the previously developed mathematical model. The control characteristic, constructed experimentally at constant generator voltage, is the control law of the magnetic shunt winding for the studied generator. The investigated version of a synchronous generator with a magnetic shunt should be used for autonomous power plants, renewable energy systems, and autonomous power supply systems
  • Ескіз
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    Мathema thical modeling of a synchro nous generator with combined excitation
    (Український державний університет залізничного транспорту, ПП «Технологічний центр», 2020) Chumack, Vadim; Tsyvinskyi, Serhii; Kovalenko, Mykhailo; Ponomarev, Alexej; Tkachuk, Ihor
    нтерес представляють генератори класичної кон струкції – із циліндричним статором та ротором. Це обу мовлено тим, що дана конструкція є найбільш розповсюд женою, простою та технологічною. Результатом розробки таких електричних машин є можливість створення об’єд наної серії асинхронних двигунів та магнітоелектричних синхронних машин. В цих машинах заміна КЗ ротора на ротор з постійними магнітами та керованим робочим магнітним потоком перетворює асинхронну машину в магнітоелектричну синхронну. Всі існуючі генератори із постійними магнітами мають головний недолік: практич но відсутня можливість регулювання вихідної напруги та в окремих випадках потужності. Це особливо актуально для автономних енергосистем. Відомі методи регулюван ня вихідної напруги призводять до підвищення вартості, зниження надійності, погіршення вагогабаритних показ ників. Розроблено тривимірну польову математичну модель магнітоелектричного синхронного генератора із постій ними магнітами. Модель реалізована методом скінченних елементів в програмному пакеті COMSOL Multiphysics. Показано розподіл електромагнітного поля в активній зоні генератора при управлінні і без нього. Розраховано вплив струму управління в підмагнічуючій обмотці на зовнішні характеристики генератора при різному коефі цієнті потужності навантаження. За допомогою розро бленої моделі синтезовано закон управління струмом в підмагнічуючій обмотці при зміні навантаження в широ ких межах. Отримані результати показують, що існує можли вість регулювання вихідної напруги генератора з постій ними магнітами з допомогою використання додаткової підмагнічуючої обмотки. Обмотка виконує роль електро магнітного шунта для основного магнітного потоку, який створюють постійні магніти. Аналіз результатів пока зав, що існує можливість в широких межах регулювати вихідну напругу генератора із постійними магнітами в межах – 35 %, +15 %