Wyniki 1-4 spośród 4 dla zapytania: authorDesc:"Mihail DIGALOVSKI"

Calculation of electric arc furnace secondary circuit - analytical and numerical approach DOI:10.15199/48.2016.12.06

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The paper presents the procedure of electric arc furnace secondary circuit calculations. The separate parameters that form the furnace circuit impedance have been determined. The operating current for given power factor has been calculated and verified. To get better insight of the operating conditions of the arc furnace, thermal and stress analysis of the secondary delta closure have been performed. The procedure and the results are verified by measurements over 110 tone electric arc furnace with rated power of 110MVA. Streszczenie. W artykule przedstawiono procedurę obliczeń obwodu wtórnego elektrycznego pieca łukowego. Zostały określone poszczególne parametry, które tworzą impedancję obwodu pieca. Między innymi został obliczony i zweryfikowany prąd przy danym współczynniku mocy. W pracy przedstawiono wyniki przeprowadzonej analizy termicznej i naprężeń w przypadku zwarcia obwodu wtórnego, wykonane celem lepszego zrozumienia warunków pracy pieca łukowego. Procedura i wyniki pomiarów zostały zweryfikowane przez pomiary w ponad 110 tonowym piecu łukowym o mocy znamionowej 110MVA. (Obliczanie obwodu wtórnego elektrycznego pieca łukowego - podejście analityczne i numeryczne). Keywords: electric arc furnace, power calculations, heat, stress Słowa kluczowe: elektryczny piec łukowy, obliczenia elektryczne, ciepło, naprężenia. Introduction Electric arc furnaces (EAF) are electric process heating systems that heat materials by means of an electric arc [1,2,3]. The modern EAF is a highly efficient recycler of scrap iron or other ferrous material used for making carbon and alloy steel. The electric arc furnace operates as a batch melting process producing batches of molten steel. Typically the batch cycle time is less than 60 minutes. The EAF is one of the largest consumers of electrical energy in most of the power systems. According to the International Iron and Steel Institute (IISI) report [4] the annual crude steel production July 2016 ver[...]

An innovative approach to optimisation of E-I core inductor DOI:10.12915/pe.2014.12.36

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In the paper a new approach for optimisation and designing an E-I inductor, by using the Taguchi Design of Experiments (DoE) technique is presented. The proposed technique is applied on an existing iron core inductor. The target of optimisation is to reduce the total mass of active materials, preferably focussing on copper mass, while the required value of magnetising inductance is kept inside the prescribed bounds. Additional constraints are also considered. The inductor lamination geometry and properties of active materials (iron core and copper wire) are kept the same. The method incorporates application of 3D FEM as virtual design tool, to prove the optimisation results Streszczenie. W artykule przedstawiono nowe podejście w optymalizacji i projektowaniu induktora z rdzeniem E-I przy wykorzystaniu techniki Design of Experiment (zaproponowanej przez Dr. Taguchi. Proponowana technika zastosowana jest dla istniejącego rdzenia induktora. Celem optymalizacji jest redukcja całkowitej masy materiałów aktywnych ze szczególnym uwzględnieniem masy miedzi przy zachowaniu wymaganej wartości indukcyjności w przewidzianych granicach. Dodatkowe ograniczenia również zostały rozważone. Warstwowa geometria induktora i właściwości materiałów aktywnych (rdzeń i przewody miedziane)zostały zachowane bez zmian. Metoda wykorzystuje trójwymiarową analizę metodą elementów skończonych do potwierdzenia wyników optymalizacji. (Innowacyjne podejście do optymalizacji induktora z rdzeniem E-I) Keywords: E-I core inductor, Optimisation, Taguchi design of experiments (DoE), Finite element analysis, Słowa kluczowe: induktor z rdzeniem E-I, optymalizacja, Design of Experiments, analiza elementowo-skończeniowa. doi:10.12915/pe.2014.12.36 Introduction Recently, within the engineering community, there is a significant interest for optimal designing of electromagnetic devices. In engineering practice the concept of optimization procedure means creating better and more econo[...]

Space vector modulation techniques for improved stator flux trajectory in direct torque control of induction motor DOI:10.15199/48.2019.05.04

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In direct torque vector control (DTC) systems, voltage source inverter (VSI) is describe in discrete mode as a source of constant amplitude voltage sources with strictly controlled direction, time duration and limited sample frequency. The output vector voltage vector may take up to seven different states and is altered in precisely specified time only at the command of given controlling signal. Therefore, the VSI dynamic state is discrete both in time and quantity. The stator flux space vector is used as a fundamental value in designing the control circuits of induction machine (IM). In this paper, therefore, the basic characteristics of stator flux space vector will be analysed in such a control concept for two different types of space vector modulation (SVM) techniques one is full block space vector modulation and second is called pulse edge space vector modulation.Advantages of the trajectory The selection of the switch-on and switch-off states of the power switches (Fig.1) is carried out so that the error between the real value of and the reference (assigned) value of moves within the limits of as defined by the hysteresis band of the flux controller. However, the selection of the states of the power switches not only depends on the absolute error value but also on the rotation direction of vector . For this purpose, the stationary reference domain is divided into 6 (six) equal parts (zones). Each zone has its own carrier voltage space vector. Thus, for instance, the carrier vector of the ‘0’ zone is vector . For a positive rotation direction (clockwise) the subsequent two voltage space vectors, and switch on respectively, depending on whether the upper or lower limit of the hysteresis band has been reached. For a negative rotation direction (counter clockwise) the corresponding vectors or switch on depending on whether the upper or lower limit of the hysteresis control band has been reached. The stator f[...]

ViMeLa Project: An innovative concept for teaching mechatronics using virtual reality DOI:10.15199/48.2019.05.05

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Nowadays, traditional education and teaching methods, although with significantly improved teaching techniques, can not keep enough interest of the students that grew up with Internet, mobiles and tablets. Especially sensitive to these issues are students in engineering, in particular, in mechatronics. Modern information technology is rapidly being adopted in Mechatronics Engineering education as a tool for enriching the practical experience of the students. The practical training is a vital part of Mechatronics Engineering education [1]. However, the high cost needed to implement laboratory experiments (for educational purposes) led to development of virtual facilities where physical systems can be virtually controlled via the Virtual Reality (VR) simulations. Multimedia and VR technologies offer great potential for presenting theory and laboratory experiments in an enhancing and interesting, but in an economical, way. Teaching and learning Mechatronics Mechatronics is synergy and interaction of mechanical, electrical and computer systems as seen in Fig. 1. Hence, it is an interactive combination of mechanical engineering, electronic control and computer technology, with the aim of achieving an ideal balance between mechanical structure and its overall control and performance. Fig.1. Structure and key elements of mechatronics Currently, mechatronics classes are divided into two parts: the theoretical lectures and laboratory courses with experiments following the "learning by doing" model. Expensive equipment and limited time for training do not provide sufficient educational platforms [2,3]. In some cases the students conduct based simulations and learn how mechatronic systems and devices operate in reality, despite it may seem abstract and unclear for students, and does not fully reflect the physical phenomena of particular processes. The described drawbacks of mechatronics study are greatly improved when classroom teac[...]

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