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Search results for: dc micro grid
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Fluctuation-enhanced scent sensing using a single gas sensor
PublicationScent or aroma sensing during aromatherapy can be carried out by applying only a single resistance gas sensor (TGS - Taguchi Gas Sensors). This paper considers the efficiency of detection of essential oils by DC resistance and its fluctuations observed in TGS sensors. A detailed study has been conducted for scents emitted by five popular essential oils using three sensor types (TGS 2600, TGS 2602, TGS 823). The research was focused...
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The content of high-intensity sweeteners in different categories of foods available on the Polish market
PublicationThe objective of this study was to measure the concentrations of nine high-intensity sweeteners (acesulfame-K, aspartame, alitame, cyclamate, dulcin, neohesperidin DC, neotame, saccharin and sucralose) in different categories of food available on the Polish market. Over 170 samples of different brands of beverages, yoghurts, fruit preparations, vegetable preserves and fish products were analysed using an analytical procedure based...
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Dynamic variables limitation for backstepping control of induction machine and voltage source converter
PublicationDynamic variables limitation for backstepping control of induction machine and voltage source converter The paper presents the method of control of an induction squirrel-cage machine supplied by a voltage source converter. The presented idea is based on an innovative method of the voltage source converter control, consisting in direct joining of the motor control system with the voltage source rectifier control system. The combined...
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Parameter selection of an adaptive PI state observer for an induction motor
PublicationThe paper discusses problems connected with the parameters selection of the proportional-integral observer, designed for recon- struction of magnetic fluxes and angular speed of an induction motor. The selection is performed in several stages that are focused on different criteria. The first stage consists in selecting observer’s gains and provides desired dynamical properties, taking into consideration immunity to disturbances and...
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A Quasi-2D MOSFET Model — 2D-to-Quasi-2D Transformation
PublicationA quasi-two-dimensional (quasi-2D) representation of the MOSFET channel is proposed in this work. The representation lays the foundations for a quasi 2D MOSFET model. The quasi 2D model is a result of a 2D into quasi 2D transformation. The basis for the transformation are an analysis of a current density vector field and such phenomena as Gradual Channel Detachment Effect (GCDE), Channel Thickness Modulation Effect (CTME), and...
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Superconducting properties and electronic structure of NaBi
PublicationResistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. Tc, the electronic contribution to the specific heat γ, the ΔCp/γTc ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol−1 K−2, 0.78, and 140 K respectively. The calculated electron–phonon coupling constant (λep = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence...
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Development of an emulation platform for synchronous machine power generation system using a nonlinear functional level model
PublicationThe article presents the Power Hardware in the Loop (PHIL) approach for an autonomous power system analysis based on the synchronous generator model incorporating magnetic saturation effects. The model was prepared in the MATLAB/Simulink environment and then compiled into the C language for the PHIL platform implementation. The 150 kVA bidirectional DC/AC commercial-grade converter was used to emulate the synchronous generator....
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Solutions of Power Electronics Converter for the Shore - to - Ship Power Systems
PublicationW artykule poruszono tematykę zasilania statków zacumowanych w porcie z lądowej sieci elektroenergetycznej poprzez wykorzystanie nowoczesnych konstrukcji przekształtników energoelektronicznych. Zaproponowano budowę sieci dystrybucyjnej prądu stałego, przewoźnej platformy zasilającej oraz zastosowanie zasobników energii
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Experimental research of the stability of steel cylindricalshell subjected to circumferential compression
PublicationAt the Department of Metal Structures Gdańsk University of Technology, experiments have been performed on the stability of shell of steel cylindrical models. The experiments have been carried on a test bench built at the Department. The design based on other test benches which were created in the past by other scientists, where modernized by the courtesy of companies that offer modern solutions. The test bench enables to generate...
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Sound Field Intensity Measurements and Visualization around the Human Head Model . Rozkłąd natężenia pola akustycznego w komorze bezechowej obecności sztucznej głowy i w przypadku braku jej obecności
PublicationThe main goal of this research study was to measure and visualize sound field intensity distribution in and without presence of the human head model. Measurements were performed in the anechoic chamber with the 5 cm grid. Experimental setup consisted of a multitone generator, two loudspeakers, human head model, intensimetric probe, the Cartesian robot applied for precise positioning of the acoustic sensor, and an analyzer. Based...
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FDTD-Compatible Green's function based on scalar discrete Green's function and multidimensional Z-transform
PublicationIn this contribution, a new formulation of the discrete Green's function (DGF) is presented for the finitedifference time-domain (FDTD) grid. Recently, dyadic DGF has been derived from the impulse response of the discretized scalar wave equation (i.e., scalar DGF) with the use of the multidimensional Z-transform. Its software implementation is straightforward because only elementary functions are involved and a single function...
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The Innovative Faculty for Innovative Technologies
PublicationA leaflet describing Faculty of Electronics, Telecommunications and Informatics, Gdańsk University of Technology. Multimedia Systems Department described laboratories and prototypes of: Auditory-visual attention stimulator, Automatic video event detection, Object re-identification application for multi-camera surveillance systems, Object Tracking and Automatic Master-Slave PTZ Camera Positioning System, Passive Acoustic Radar,...
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The finite-difference simulation of x-rays propagation through a system of lenses
PublicationThe propagation of X-ray waves through an optical system consisting of 33 aluminum X-ray refractive lenses is considered. For solving the problem, a finite-difference method is suggested and investigated. It is shown that very small steps of the difference grid are necessary for reliable computation of propagation of X-ray waves through the system of lenses. It is shown that the wave phase is a function very quickly increasing...
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Establishment of the Right of Electricity Transmission Easement Through Court Proceedings
PublicationIncluding the amendment of the Civil Code Act on May 30, 2008, issues related to the right of easement of transmission were introduced to it. Such a regulation was necessary in view of the need to define the legal status of transmission facilities, existing and designed on real estate property. The purpose of the study is to analyze issues related to the definition of the spatial extent of the law of transmission easement for power...
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Uterus, unspecified - Female, 44 - Tissue image [413073001884211]
Open Research DataThis is the histopathological image of OVARY tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Uterus, unspecified - Female, 44 - Tissue image [4130730018849921]
Open Research DataThis is the histopathological image of OVARY tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Uterus, unspecified - Female, 44 - Tissue image [4130730018843031]
Open Research DataThis is the histopathological image of OVARY tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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High-density polyethylene/EPDM rubber blend composites of boron compounds for neutron shielding application
PublicationNovel materials with neutron shielding property were fabricated by incorporating boron compounds into highdensity polyethylene (HDPE)/Ethylene propylene diene monomer rubber (EPDM) blends. A detailed investigation on the morphological, thermal, mechanical, and neutron attenuation properties of suitable proportion of HDPE/EPDM blend with boric acid (BA), boron carbide (BC), and nano boron carbide (NBC) were performed. Morphology...
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The Determinants of False Self-Employment: A Survey of Polish Enterprises
PublicationThe main goal of this article is to advance the emergent research on tax evasion in Poland in the form of false self-employment (FSE), in particular to identify its causes. The dependent character of some self-employed workers is a big problem in the Polish economy, which has been completely unexplored because of the lack of available data. In this article, we use data from a survey of Polish companies. Our empirical results show...
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The effect of laser on metal surfaces for multidisciplinary usage in material and thermal engineering
PublicationThe subject of heat transfer and cooling systems is still a matter of contention in many different fields of science and industry. Infrigidation is much more difficult than warming, and so, much more needed in more and more different devices, starting from massive industrial machinery and air conditioning in commercial buildings, up to micro and nano-surgery tools. In fact, the size of many cooling systems is still a problem. It...
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Underwater Wet Repair Welding of API 5L X65M Pipeline Steel
PublicationThis paper presents results of the research of effect of polymer insulation of pipeline made of API 5L X65M steel as well as underwater wet welding parameters on properties of joints made by covered electrodes. Effect of heat input on structure and hardness of joints during repair of underwater pipeline was analyzed. Welding defects like microcracks, micro-lacks of fusion, slag inclusions, as well as HAZ hardness increase over...
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Chemistry of non-precipitation components of wet deposition with Poland as an example
PublicationW pracy przedstawiono badania dotyczące chemizmu osadów atmosferycznych pobieranych na terenie Polski w okresie od 2004 do 2007 roku. Średni skład jonowy (TIC) dla rosy, szronu i mgły (w stanie ciekłym i stałym) wynosił odpowiednio 2147, 1929 i 1014 µeq/l, gdzie typowy skład jonowy TIC dla opadów atmosferycznych wynosi 318 µeq/l. Dla wszystkich typów osadów atmosferycznych różne jony pełnią ważną rolę: Ca2+ i SO42-...
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Capacity Transforming challenges into opportunities
PublicationThe Urban Initiative Laboratory (UIL) aims to upgrade the smart city concept in Gdańsk by introducing the Food-Water-Energy (FWE) nexus to the city. It was agreed in the CRUNCH international consortium that projects on different scales would be implemented in the individual countries to test the Integrated Decision Supportive system platform, which would, in principle, concern urban scale. The regular urban scale was to be researched...
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Pantographic metamaterials: an example of mathematically driven design and of its technological challenges
PublicationIn this paper, we account for the research efforts that have been started, for some among us, already since 2003, and aimed to the design of a class of exotic architectured, optimized (meta) materials. At the first stage of these efforts, as it often happens, the research was based on the results of mathematical investigations. The problem to be solved was stated as follows: determine the material (micro)structure governed by those...
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Bezczujnikowe sterowanie generatorem klatkowym w stanach lotnego startu elektrowni wiatrowej
PublicationElektrownie wiatrowe pracujące na sieć i wyposażone w przekształtniki dwukierunkowe AC-DC-AC, dzięki zastosowaniu generatorówindukcyjnych klatkowych mogą zapewniać efektywne generowanie energii w szerokim zakresie zmian wiatru. W artykule przedstawiono analizęlotnego startu elektrowni wiatrowej z generatorem klatkowym i cyfrowym układem sterowania. Przedstawiono wyniki symulacji lotnego startu generatora klatkowego w układzie ze...
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Układy sterowania bramkowego tranzystorów z węglika krzemu SiC JFET w falownikach napięcia
PublicationZastosowanie technologii węglika krzemu (SiC) w falownikach napięcia pozwala na zwiększenie częstotliwości przełączeń oraz temperatury pracy przyrządów półprzewodnikowych. W celu zapewnienia minimalizacji strat oraz określonych właściwości dynamicznych tranzystorów z węglika krzemu wymagane jest stosowanie zaawansowanych układów sterowania bramkowego. W referacie przedstawiono analizę teoretyczną, wyniki badań symulacyjnych oraz...
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Determination of the ionic conductivity of Sr-doped lanthanum manganite by modified Hebb–Wagner technique
PublicationThe Hebb–Wagne rpolarization method with the electron blocking electrode has been discussed in this paper in aim to determine a partial ionic conductivity of Sr-doped lanthanum manganite.The “limiting current” in the proposed system was measured using the two-point DC technique with additional Pt electrode between LSM and blocking electrode.The electrochemical model based on bulk diffusion processes and Boltzmann statistics has...
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The domination of ionic conductivity in tetragonal phase of the organometal halide perovskite CH3NH3PbI3-xClx
PublicationOrganometal trihalide perovskites have recently gained extreme attention due to their high solar energy conversion in photovoltaic cells. Here, we investigate the contribution of iodide ions to a total conductivity of the mixed lead halide perovskite CH3NH3PbI3−xClx with a use of the modified DC Hebb–Wagner polarization method. It has been identified that an ionic conductivity dominates in tetragonal phase which is associated with room...
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Evaluation of Praseodymium and Gadolinium Doped Ceria as a Possible Barrier Layer Material for Solid Oxide Cells
PublicationIn this work, nanocrystalline layers based on the Pr, Gd co-doped CeO2 were investigated. For the preparation of thin layers, lowtemperature spray pyrolysis technique was used. Different stoichiometries of the layers were produced for comparison on polished sapphire substrates. The microstructure of the prepared thin layers was studied by scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD)....
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Aktualne Problemy w Elektroenergetyce” – APE’19
EventsWydział Elektrotechniki i Automatyki Politechniki Gdańskiej, Katedra Elektroenergetyki zaprasza do udziału w XIX Konferencji Naukowej „Aktualne Problemy w Elektroenergetyce” – APE’19
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Audible noise in ship’s electrical drive systems with frequency converters
Open Research DataThe presented dataset is part of research focusing on the impact of the ship's electrical drive systems with frequency converters on vibrations and the level of audible noise on ships.
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Zależność pomiędzy wielkością przedsiębiorstwa a strukturą źródeł finansowania
PublicationW artykule przedstawiono różnice w sposobie kształtowania struktury źródeł finansowania pomiędzy małymi, średnimi i dużymi przedsiębiorstwami. W trakcie przeprowadzonych badań uwzględniono 97 471 sprawozdań finansowych przedsiębiorstw, prowadzących działalność gospodarczą w 12 różnych działach polskiej gospodarki narodowej. Do potwierdzenia zróżnicowania struktury kapitałowej w zależności od wielkości przedsiębiorstwa wykorzystano...
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Systems Engineering Requirements for Rotating Machines (PG-00060237)
e-Learning CoursesTurbiny wiatrowe, gazowe, mikroturbiny, silniki lotnicze, turbosprężarki i inne systemy mechaniczne to przykłady maszyn wirujących, które wymagają wysoko wykwalifikowanych inżynierów. Powinni oni zrozumieć złożoność procesów projektowania i produkcji, w tym wytwarzania przyrostowego, oraz konserwacji prognostycznej opartej na inżynierii cyfrowej dla bezawaryjnej pracy silnika. Wind, gas, micro turbines, aircraft engines, turbochargers,...
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Control Strategy of a Five-Phase Induction Machine Supplied by the Current Source Inverter With the Third Harmonic Injection
PublicationIn the five-phase induction machine (IM), it is possible to better use the electromagnetic circuit than in the three-phase IM. This requires the use of an adequate converter system which will be supplied by an induction machine. The electric drive system described, in this article, includes the five-phase induction machine supplied by the current source inverter (CSI). The proposed novelty—not presented previously—is the control...
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UV-assisted fluctuation-enhanced gas sensing by ink-printed MoS2 devices
PublicationIn this work, MoS2 flakes were printed on ceramic substrates and investigated toward 1–10 ppm of nitrogen dioxide (NO2), 2–12 ppm of ammonia (NH3), and 2–12 ppm acetone (C3H6O) under UV light (275 nm). The structure of overlapping MoS2 flakes and UV light assistance affected high responsivity to NO2 when DC resistance was monitored, and superior sensitivity to NH3 was obtained from the low-frequency noise spectra. MoS2 exhibited...
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A new concept of PWM duty cycle computation using the Barycentric Coordinates in a Three-Dimensional voltage vectors arrangement
PublicationThe paper presents a novel approach to the Pulse Width Modulation (PWM) duty cycle computing for complex or irregular voltage vector arrangements in the two (2D) and three–dimensional (3D) Cartesian coordinate systems. The given vectors arrangement can be built using at least three vectors or collections with variable number of involved vectors (i.e. virtual vectors). Graphically, these vectors form a convex figure, in particular,...
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Magnetic anisotropy and structural flexibility in the f ield-induced single ion magnets [Co{(OPPh2) (EPPh2)N}2], E = S, Se, explored by experimental and computational methods
PublicationDuring the last few years, a large number of mononuclear Co(II) complexes of various coordination geometries have been explored as potential single ion magnets (SIMs). In the work presented herein, the Co(II) S = 3/2 tetrahedral [Co{(OPPh2)(EPPh2)N}2], E = S, Se, complexes (abbreviated as CoO2E2), bearing chalcogenated mixed donor-atom imidodiphosphinato ligands, were studied by both experimental and computational techniques. Specifically,...
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Tracking Fluorescent Dye Dispersion from an Unmanned Aerial Vehicle
PublicationCommercial unmanned aerial vehicles continue to gain popularity and their use for collecting image data and recording new phenomena is becoming more frequent. This study presents an effective method for measuring the concentration of fluorescent dyes (fluorescein and Rhodamine WT) for the purpose of providing a mathematical dispersion model. Image data obtained using a typical visible-light camera was used to measure the concentration...
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Techno-economic assessment of cooperation of hybrid renewable energy sources with hydrogen storage
PublicationThe paper presents a technical and economic analysis of the power supply for a model industrial facility with the use of the most promising renewable energy sources (RES), supported by a hydrogen energy storage. This scenario was compared with the variants of supplying the facility directly from the grid and from RES without energy storage. A strategy was proposed for powering the plant aimed at maximising self-consumption of self-generated...
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Parallel implementation of the DGF-FDTD method on GPU Using the CUDA technology
PublicationThe discrete Green's function (DGF) formulation of the finite-difference time-domain method (FDTD) is accelerated on a graphics processing unit (GPU) by means of the Compute Unified Device Architecture (CUDA) technology. In the developed implementation of the DGF-FDTD method, a new analytic expression for dyadic DGF derived based on scalar DGF is employed in computations. The DGF-FDTD method on GPU returns solutions that are compatible...
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Non-Salient Brushless Synchronous Generator Main Exciter Design for More Electric Aircraft
PublicationThis paper presents a prototype of high speed brushless synchronous generators (BSG) design for the application in autonomous electric power generation systems (e.g., airplane power grid). Commonly used salient pole field of the main generator part of BSG was replaced with a prototype non-salient pole field. The main objective of the research is an investigation into the advantages and disadvantages of a cylindrical field of the...
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Towards rainfall interception capacity estimation using ALS LiDAR data
PublicationIn this study we develop a spatial model for interception capacity of vegetation based on LiDAR data. The study is conducted in the natural wetland river valley dominated meadows, reeds and small bushes. The multiple regression model was chosen to relate the field measurements of interception capacity and LiDAR statistics at 2m grid. The optimal model was chosen by stepwise selection and further manual variables selection resulting...
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Modern technologies in energy demand reducing of public transport — Practical applications
PublicationCity of Gdynia (Poland) exploits one of the most modern trolleybus network in Europe, which has been involved in many projects related to the reduction of energy consumption. Some of them are connected with the improving of energy breaking recovery usage. An experimental stationary storage system at Północna substation, which was tested in 2012-2014, is a bright example of a system which is connected with the improving of the...
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Long-term hindcast simulation of water temperature and salinity in the Baltic Sea
Open Research DataThe dataset contains the results of numerical modelling of water temperature and salinity over a period of 50 years (1958-2007) in the Baltic Sea. A long-term hindcast simulation was performed using a three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). The hydrodynamic...
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Long-term hindcast simulation of currents in the Baltic Sea
Open Research DataThe dataset contains the results of numerical modelling of currents over a period of 50 years (1958-2007) in the Baltic Sea . A long-term hindcast simulation was performed using a three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). The hydrodynamic model was coupled...
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Emotion Recognition - the need for a complete analysis of the phenomenon of expression formation
PublicationThis article shows how complex emotions are. This has been proven by the analysis of the changes that occur on the face. The authors present the problem of image analysis for the purpose of identifying emotions. In addition, they point out the importance of recording the phenomenon of the development of emotions on the human face with the use of high-speed cameras, which allows the detection of micro expression. The work that was...
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Przesył energii elektrycznej - potrzeby,progi i bariery
PublicationW artykule przeanalizowano stan aktualny i kierunki rozwoju krajowego systemu przesy ł owego w kontek ś cie potrzeb gospodarki krajowej. Przedstawiono znaczenie sieci przesy ł owych oraz rol ę operatorów systemu przesy ł owego i systemów dystrybucyjnych w sektorze energetycznym. Oceniono mo ż liwo ś ci rozwoju przy uwzgl ę dnieniu aktualnych prognoz zapotrzebowania na energi ę , wytyczono potencjalne...
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MODELOWANIE TURBINY WIATROWEJ Z DWOMA PRZECIWBIEŻNIE OBRACAJĄCYMI SIĘ WIRNIKAMI
PublicationW artykule przedstawiono sposoby modelowania dwuwirnikowej turbiny wiatrowej z wykorzystaniem technik Obliczeniowej Mechaniki Płynów. Omówiono uproszczone metody modelowania Actuator Disc i Actuator Line Method oraz aspekty związane z dokładnym odwzorowaniem turbiny na siatce obliczeniowej. Zaprezentowano przykładowe wyniki obliczeń turbiny dwuwirnikowej złożonej z wirników NREL o mocy nominalnej 5 MW każdy. Do wykonania badań...
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Badania eksperymentalne prostownika osiemnastopulsowego o mocy 150 kVA z opcjonalnym szeregowym energetycznym filtrem aktywnym
PublicationW artykule przedstawiono system sterowania oraz wybrane wyniki badań eksperymentalnych przekształtnika AC / DC składającego się z osiemnastopulsowego diodowego prostownika na bazie dławików sprzężonych i szeregowego energetycznego filtra aktywnego. Przebadano i porównano trzy konfiguracje przekształtnika o mocy 150kVA: (1) osiemnastopulsowy prostownik bez dodatkowych elementów, (2) prostownik z dodatkowym dławikiem sieciowym oraz...
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Oddziaływanie przekształtników energoelektronicznych dużej mocy na jakość energii elektrycznej
PublicationW referacie przedstawiono zagadnienia związane z oddziaływaniem układów przekształtnikowych AC/DC na sieć zasilającą poprzez generowanie prądów odkształconych. Przedstawione wyniki badań porównawczych emisji zaburzeń przewodzonych układów prostownikowych klasycznych (diodowych) oraz nowoczesnych (tranzystorowych) wykazują znaczne zwiększenie emisji w zakresie stosowanych częstotliwości modulacji w typowych aplikacjach przemysłowych....