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Search results for: NPC CONVERTER, NEUTRAL POINT VOLTAGE BALANCING, BRAKE CIRCUIT
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Nonlinear Control of a Doubly Fed Generator Supplied by a Current Source Inverter
PublicationNowadays, wind turbines based on a doubly fed induction generator (DFIG) are a commonly used solution in the wind industry. The standard converter topology used in these systems is the voltage source inverter (VSI). The use of reverse-blocking insulated gate bipolar transistor (RB-IGBT) in the current source inverter topology (CSI), which is an alternative topology, opens new possibilities of control methods. This paper presents...
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OCENA WŁAŚCIWOŚCI ROZLEGŁYCH SYSTEMÓW UZIEMIEŃ PRACUJĄCYCH W UKŁADACH OCHRONY ODGROMOWEJ
PublicationW wyniku połączenia wszystkich elementów uziemionych w obiekcie budowlanym do szyny ekwipotencjalnej powstaje często bardzo rozległy system uziemień. Ocena tak rozległego systemu za pomocą metod wykorzystujących przebiegi wolnozmienne prowadzi do zbyt optymistycznych wniosków odnośnie do ich właściwości podczas odprowadzania prądów wyładowań atmosferycznych. Pomiary z zastosowaniem metody wykorzystującej przebiegi impulsowe pomiaru...
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ASPEKTY BEZPIECZEŃSTWA W OCENIE WYNIKÓW POMIARÓW UZIEMIEŃ ODGROMOWYCH
PublicationOcena rozległego systemu za pomocą metod wykorzystujących przebiegi wolnozmienne prowadzi do zbyt optymistycznych wniosków odnośnie ich właściwości podczas odprowadzania prądów wyładowań atmosferycznych. Bardziej bezpieczne wnioski powstają w wyniku pomiarów z zastosowaniem metody wykorzystującej przebiegi impulsowe, ponieważ wtedy jest uwzględniana tylko ta część nawet bardzo rozległego systemu uziemień, która bierze udział w...
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Rapid multi-objective design of integrated on-chip inductors by means of Pareto front exploration and design extrapolation
PublicationIdentification of the best trade-offs between conflicting design objectives allows for making educated design decisions as well as assessing suitability of a given component or circuit for a specific application. In case of inductors, the typical objectives include maximization of the quality factor and minimization of the layout area, as well as maintaining a required inductance at a given operating frequency. This work demonstrates...
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Experimental verification of a new method of loop resistance testing in low voltage systems with residual current devices
PublicationA periodical verification of the effectiveness of protection against electric shock shall be performed in low voltage systems. The scope of this verification includes loop impedance/resistance testing. If a residual current device is installed in a tested circuit, this testing is problematic. A residual current device trips out during the test, because of the high value of measurement current. This precludes the execution of the...
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Synthesis and Testing of BCZY/LNZ Mixed Proton–electron Conducting Composites for Fuel Cell Applications
PublicationA composite of BaCe0.6Zr0.2Y0.2O3–δ and Li2O:NiO:ZnO was investigated for fuel cell applications. The composite was successfully synthesized and its phase stability was confirmed at temperatures up to 900 °C. The influence of sintering and pressing aids on density was also investigated. Electrical properties were measured. DC electrical conductivity was about 8•10-4 S/m at 845 K. Open circuit voltage measurements in wet hydrogen...
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Development of beltless respiration and heartbeat sensor based on flexible piezoelectric film
PublicationThe main goal of this work is to report initial development on a respiration and heartbeat measurement sensor that can be used in continuous monitoring conditions at a minimal impact on the patient. General description of the sensor, consisting of a PVDF film and the bonding layer, is given. Open-circuit voltage generated by the sensor is estimated by analytical and numerical calculations. Analog and digital interface used to extract...
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Tripping limitations of residual current devices in photovoltaic installations
PublicationIn electrical installations with photovoltaic sources of energy, earth fault current may comprise alternating current component and direct current component. The waveform shape of this earth fault current mainly depends on the point of the fault and the properties of a photovoltaic power electronics converter. The waveform shape of the current influences operation of protection devices, especially tripping threshold of residual...
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A measurement method for lossy capacitive relative humidity sensors based on a direct sensor-to-microcontroller interface circuit
PublicationA new time-domain measurement method for determining the capacitance and resistance values of lossy relative humidity capacitive sensors is presented. The method is based on a direct sensor-to-microcontroller interface for microcontrollers with internal analog comparators and timers. The interface circuit consists only of four reference resistors (two reference resistors if a microcontroller includes a voltage reference source),...
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A High-Efficient Low-Voltage Rectifier for CMOS Technology
PublicationA new configuration of rectifier suiting CMOS technology is presented. The rectifier consists of only two nchannel MOS transistors, two capacitors and two resistors; for this reason it is very favourable in manufacturing in CMOS technology. With these features the rectifier is easy to design and cheap in production. Despite its simplicity, the rectifier has relatively good characteristics, the voltage and power efficiency, and...
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The voltage on bus bars of the main switchboard of the ferry electrical power system during a layover at the port
Open Research DataThe dataset is part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the measurement results carried out onboard the ferry during a layover at the port.
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Computer-Aided Calculations of Earth Potential Rise in High Voltage Overhead Lines
PublicationHigh voltage overhead power lines with earth wires comprise towers made of conductive material. Some towers are in locations where people can be expected to be either for a long time or for a short time but very frequently. Evaluation of shock hazard near such towers requires calculation of line-to-earth short-circuit current, earth current and especially earth potential rise. Number of towers in high voltage power lines can exceed...
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Ceramic composites for single-layer fuel cells
PublicationComposite materials consisting of acceptor doped lanthanum orthoniobate electrolyte phase (La0.98Ca0.02NbO4) and Li2O:NiO:ZnO semiconducting phase were synthesized. The precursor powder of La0.98Ca0.02NbO4 was prepared in nanocrystalline (mechanosynthesis) and microcrystalline (solid-state synthesis) form. The composite can be applied in a single-layer fuel cell, because of the presence of two phases acting as an anode and a cathode...
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Feedback Control of Doubly-Fed Generator Connected to Current Source Converter
PublicationDoubly-fed induction generator (DFIG) system supplied by current source converter (CSC) is considered in this article. The DFIG can work in two independent modes: AC grid connection and stand-alone mode. The DFIG is connected to the ac grid directly through its stator and the CSC links the rotor side. In this mode, the active and reactive powers of the DFIG must be controlled. This article proposes two control system structures...
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Predykcyjne sterowanie równoległym filtrem aktywnym ze sprzężeniem od prądu zasilającego
PublicationArtykuł przedstawia nowatorską strategię predykcyjnego sterowania równoległym energetycznym filtrem aktywnym (EFA). Proponowane sterowanie zawiera sprzężenie zwrotne od prądu zasilającego i wiąże zalety sterowania w układzie otwartym oraz zamkniętym – szybkość reakcji na zmianę prądu odbioru i bardzo wysoką skuteczność kompensacji. Wysoka jakość prądu kompensacyjnego wynika również z zastosowania w sterowaniu algorytmów predykcyjnych,...
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Nowa metoda obliczania rozpływu prądów zwarciowych w przewodach odgromowych linii wysokiego napięcia
PublicationReferat przedstawia nowatorską metodę obliczania wartości prądów płynących w przewodach odgromowych w czasie zwarć, pozwalającą na dobór przewodów odgromowych pod względem wytrzymałości cieplnej. Proponowana metoda charakteryzuje się większą dokładnością i większą uniwersalnością niż powszechnie stosowane metody, pozwalając tym samym na dobór przewodów odgromowych z mniejszym ryzykiem niepewności. Prezentowana metoda obliczeniowa...
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The voltage on bus bars of the main switchboard of the ferry electrical power system during a sea voyage
Open Research DataThe dataset is part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the measurement results carried out onboard the ferry during a sea voyage.
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Remote current measurement with FPGA digital processing
PublicationThe work presents an implementation of a modular measurement and control systemthat controls variants of mains supply of 230V electrical equipment. The system allowsto supervise power consumption in the office electronic equipment. The system detectsthe instant of the reduced power consumption by a device and makes possible itsswitch-off in order to reduce energy cost. The current is measured with integratedcurrent/voltage converters....
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Degradation of xylose using a microbial fuel cell
PublicationIt is generally known, that many kind of microorganisms are capable of using carbohydrates as a source of carbon and energy in an environment. The biodegradation process of monosaccharides from pentoses (in this case- racemic mixture of D - and L – xylose) is an immense opportunity for an entire reduction of biological contamination to neutral compounds through MFC. The process is occurred in a single-chamber MFC, which is contained...
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Wielopoziomowe przekształtniki średniego napięcia (SN) o budowie modułowej
PublicationW artykule omówiono wybrane zagadnienia dotyczące zastosowań wielopoziomowych przekształtników średniego napięcia (SN) w układach napędowych o regulowanej prędkości, zwłaszcza w układach z izolacją od sieci zasilającej. W opracowanym przekształtniku zastosowano izolację galwaniczną od sieci zrealizowaną za pomocą izolowanych przetwornic dc-dc z transformatorami wysokiej częstotliwości (> 5 kHz). Przedstawiono zarejestrowane przebiegi...
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The time-varying low-frequency magnetic-field emitted from the ship’s inverter-fed induction motor
Open Research DataThe dataset contains the magnetic field measurement results that are part of a comprehensive study on the assessment of the magnetic field emissions onboard of the research-training vessel. The measurements were carried out, nearby the bow thruster motor fed from the inverter, during maneuvering and the sea voyage. The bow thruster is assembled in the...
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Determination of the ratio resistors in the input circuits of the NTC10k thermistor calibration system
Open Research DataThe presented data set is part of the research aimed at determining the actual characteristics of each thermistor in a package of twenty NTC10k type sensors.
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Selection of excitation signals for high-impedance spectroscopy
PublicationA method of fast impedance spectroscopy of technical objects with high impedance (|Zx| > 1 GOhm) is evaluated in this paper. An object is excited with a signal generated by a digital-to-analog converter (DAC) located on the U2531A DAQ module. Response signals proportional to current flowing through and voltage across the measured object are sampled by analog-to-digital converters (ADC) in the DAQ module. The object impedance spectrum...
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S’attaquer à la suprématie du masculin sur le féminin : le français inclusif dans les publications des universités françaises dans les réseaux sociaux
PublicationThis paper aims to examine the use of inclusive French in the Internet publications of Paris universities on their social media. Three higher education institutions were selected: Paris Dauphine-PSL University, Gustave Eiffel University, and Sorbonne Paris North University. The publications were obtained from Facebook, Instagram, and LinkedIn. Firstly, the groups of people to whom the use of inclusive French referred...
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Nowoczesne układy przekształtników wielopoziomowych do zasilania statków z lądu
PublicationW artykule poruszono tematykę zasilania statków zacumowanych w porcie z lądowej sieci elektroenergetycznej poprzez wykorzystanie nowoczesnych konstrukcji przekształtników energoelektronicznych. W treści pracy zaprezentowano porównanie dwóch topologii wysokonapięciowych przekształtników wielopoziomowych. Porównano konstrukcje przekształtników z klasycznym transformatorem wielouzwojeniowym oraz z transformatorami wysokoczęstotliwościowymi.
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EHV transmission lines wires location on line operation issues - case studies
PublicationTransmission lines towers construction affects the line parameters and influences on its operation in the future. Misguided design of the tower can lead to serious problems such as overvoltages, electric arc extinction difficulties, voltage asymmetry, resonance phenomena or increasing of magnetic field near the line. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors....
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STANY NIEUSTALONE TOWARZYSZĄCE POMIAROWI IMPEDANCJI PĘTLI ZWARCIA W OBWODACH WYJŚCIOWYCH ZASILACZY BEZPRZERWOWYCH UPS
PublicationW pracy przedstawiono metodykę i wyniki pomiarów stanów nieustalonych w zasilaczu bezprzerwowym (UPS) typu on - line. Do rejestracji zdarzeń po stronie zasilania i na wyjściu UPS wykorzystano dwa przyrządy do pomiaru jakości energii elektrycznej zsynchronizowane czasowo. Rejestratory kompresują uzyskane dane pomiarowe, co może wprowadzać dodatkowe błędy pomiaru wielkości mierzonych – napięć i prądów. Dodatkowe rejestracje oscyloskopem...
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The voltage on bus bars of the main switchboard of the car carrier electrical power system at sea trials during a bow thruster start-up
Open Research DataThe dataset is a part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. In ships' electrical power systems, disturbances occurring in voltage waveforms on bus bars of the main switchboard are connected mainly with the processes...
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Hybrid‐mode single‐slope ADC with improved linearity and reduced conversion time for CMOS image sensors
PublicationIn the paper, a single‐slope analog‐to‐digital converter (ADC) for integrated CMOS image sensor applications with an improved technique of conversion has been proposed. The proposed hybrid‐mode ADC automatically uses one of the following conversion techniques: time based (i.e. PWM) or voltage based (i.e. single‐slope). During the ADC operation, the clock frequency and reference voltage are modified in order to reduce the conversion...
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A LUMPED-CIRCUIT MODEL OF CIRCULAR PISTON TRANSDUCER FOR MODELING ITS PERFORMANCE IN DUAL FREQUENCY OPERATING MODES
PublicationThe paper presents novel network equivalent circuit of piezoceramic circular disc transducer that takes into account thickness and ra dial mode of vibrations. The starting point of the analysis is 4-port description of circular disc element representing the solution of wave equation set in radial and thickness directions. Th e approximate solution for harmonic case is represented in the form of 4x4 matrix, which is syn thesized...
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Badania laboratoryjne wybranych sposobów koordynacji regulatora transformatora blokowego oraz regulatora generatora
PublicationWprowadzenie wymogu stosowania transformatorów blokowych z przekładnią regulowaną pod obciążeniem spowodowało konieczność określenia właściwego sposobu podziału kryteriów sterowania pomiędzy regulator generatora a regulator transformatora blokowego. W referacie zwrócono uwagę na aspekt miejsca pomiaru napięć. Ma to istotny wpływ zarówno na algorytm jak i jakość regulacji. Rozważania teoretyczne zilustrowane zostały wynikami prób...
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Implementation of DEIS for reliable fault monitoring and detection in PEMFC single cells and stacks
PublicationDynamic Electrochemical Impedance Spectroscopy (DEIS) was presented as novel method for diagnostic and monitoring of PEMFC stack and single cells operation. Impedance characteristics were obtained simultaneously with current - voltage characteristics for stack and each individual cell. Impedance measurements were performed in galvanodynamic mode. It allowed to compare performance of each cell and identification of faulty cell operation...
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Effect of the let-through energy of overcurrent protective devices on the temperature of conductors during short-circuits
PublicationThe scope of the verification of low-voltage systems covers the earth fault loop impedance measurement. This measurement is usually performed with the use of low-value current meters, which force a current many times lower than the one occurring during a real short-circuit. Therefore, the international standard recommends consideration of the increase of resistance of conductors with the increase of temperature, which may occur...
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Samotestowanie toru analogowego ze wzmacniaczem w pełni różnicowym w elektronicznych systemach wbudowanych sterowanych mikrokontrole-rami
PublicationPrzedstawiono nową metodę samotestowania toru analogowego opartego na wzmacniaczu w pełni różnicowym w elektronicznych systemach wbu-dowanych sterowanych mikrokontrolerami. Bazuje ona na nowej metodzie diagnostycznej opartej na przekształceniu transformującym próbki odpo-wiedzi czasowej badanej części analogowej na pobudzenie "ujemnym" impulsem prostokątnym na wejściu Vocm na krzywe identyfikacyjne w przestrzeni pomiarowej. Metoda...
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Performance Comparison of a 650 V GaN SSFET and CoolMOS
PublicationThe new technology of wide band gap semiconductors is said to outperform up-to-date silicon devices. High voltage Gallium Nitride (GaN) transistors, now emerging in the market, have even three times shorter switching times and even four times smaller energy losses compared to the best in-class Si devices. In this paper the performance of a 650 V GaN SSFET is evaluated and compared with the newest silicon family of CoolMOS™ technology....
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Simulation Studies of Control Systems for Doubly Fed Induction Generator Supplied by the Current Source Converter
PublicationThe control system for a Doubly Fed Induction Generator (DFIG) supplied by a grid-connected Current Source Converter (CSC) is presented in this paper. Nonlinear transformation of DFIG model to the multi-scalar form is proposed. The nonlinear control strategy of active and reactive power of DFIG is realized by feedback linearization. In the proposed control scheme, the DFIG model and CSI parameters are included. Two Proportional-Integral...
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A novel approach to energy safety improvement in the marine power plants with active power surge compensator
PublicationPaper raises a point of power surges and theirs adverse effects in the marine power plants. The article explains a source of surges appearance, and presents measurements carried out on a modern ship. It discusses effects of dynamic power transients on the ship’s energy safety. Finally it proposes, a novel approach for power surge elimination, based on medium voltage active conditioner. As well as it propose the topology and control...
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Practical aspects of testing superconducting electromagnets by the capacitor discharge method taking into account the non-linearity of circuit parameters
PublicationThe article presents selected issues related to the development and testing of the diagnostics systems dedicated for superconducting electromagnets. The systems were constructed to assess the production quality of superconducting electromagnets of the SIS100 synchrotron, a new accelerator being built as part of the Facility of Antiproton and Ion Research (FAIR). One of the systems is used for automatic checking of electrical connection...
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Photoelectrochemical properties of BIMEVOX (ME=Cu, Zn, Mn) electrodes in contact with aqueous electrolyte
PublicationLayered oxide Bi4O2O11 and mixed oxides of bismuth, vanadium and a third metal (ME = Cu, Zn, Mn) were synthesized and characterized using XRD, Raman and SEM. The energy band gap (Eg) of samples determined using UV–VIS reflectance spectra equals to 2.46, 2.34, 2.27 and 2.18 eV for Bi4V2O11, BICUVOX (Bi2V1 − xCuxO5.5 − 3x/2), BIZNVOX (Bi2V1 − xZnxO5.5 − 3x/2) and BIMNVOX (Bi2V1 − xMnxO5.5 − x/2) (x = 0.1), respectively. Open circuit...
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The Impact of Wind Generation on the Transmission System
PublicationThis article has been published to investigate the im-pact of the wind power on the power system- this is a system dependent issue that requires to perform sys-tem specific impact study. This paper discusses the impact of power flow, short circuit current, power quali-ty, voltage stability and the power system during the connection of a wind farm into transmission system. W referacie omówiono wpływ farm wiatrowych na pracę systemu...
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Ocena systemów uziemień z wykorzystaniem pomiarów metodą udarową
PublicationW artykule zostały omówione procedury i wymagania stawiane systemom uziemień przez przepisy normalizacyjne z punktu widzenia ich skuteczności w systemie ochrony odgromowej. Podstawą tak sformułowanej oceny są pomiary z zastosowaniem metody udarowej. Metoda taka okazuje się bardzo przydatna zwłaszcza w przypadku uziemień rozległych, jakie pojawiają się we współczesnych obiektach wskutek połączenia różnych elementów uziemiających...
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Highly stable CsFAPbIBr perovskite solar cells with dominant bulk recombination at real operating temperatures
PublicationMixed-cation mixed-halide perovskite solar cells have been characterized in DC at different temperatures (from −20 °C up to 50 °C) and the time evolution of the device efficiency has been assessed using different degradation protocols (indoors and outdoors). The completely planar p–i–n structure is ITO/CuNiOx/PTAA/CsFAPbIBr/PCBM/PEI/Ag. Pristine current–voltage characteristics barely show hysteresis, at any temperature. Open circuit...
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Low-cost EM-Simulation-based Multi-objective Design Optimization of Miniaturized Microwave Structures
PublicationIn this work, a simple yet reliable technique for fast multi-objective design optimization of miniaturized microwave structures is discussed. The proposed methodology is based on point-by-point identification of a Pareto-optimal set of designs representing the best possible trade-offs between conflicting objectives such as electrical performance parameters as well as the size of the structure of interest. For the sake of computational...
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Szybkie uziemniki do ograniczania skutków zwarć łukowych w okrętowych rozdzielnicach SN
PublicationW artykule scharakteryzowano moc i napięcie łuku, jak również przedstawiono model termodynamiczny służący do obliczania ciśnienia i temperatury gazów w otoczeniu łuku zwarciowego. Przedstawiono przykładowy układ elektrowni okrętowej i zasilania najważniejszych odbiorników na statku do przewozu gazu ziemnego w stanie ciekłym. Na podstawie parametrów prądnic i silników odbiorników zasilanych z rozdzielnicy głównej obliczono prądy...
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The Influence of a Photovoltaic Micro-Installation on the Low-Frequency Parameters of Electricity at PCC and Its Impact on the Thermal Characteristics of Selected Devices
PublicationThis manuscript illustrates the measurement results of parameters describing the quality of energy at the PCC (point of common coupling) of a photovoltaic micro-installation that can significantly affect devices in the same power grid. The analyses reflecting heating of selected devices used in domestic installations, which were performed in an isolated laboratory environment, are also indicated. The conducted study aimed at checking...
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Role of surface recombination in perovskite solar cells at the interface of HTL/CH3NH3PbI3
PublicationIn order to achieve the highest performance of organometal trihalide perovskite solar cells, it is required to recognize the dominant mechanisms which play a key role in a perovskite material. In the following studies, we have focused on the interfacial recombination between the hole transporting layer (HTL) and the perovskite CH3NH3PbI3 in solar cell devices with p–i–n architecture. It has been shown that Cu:NiOx : used as HTL...
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Performance Evaluation of a 650V E-HEMT GaN Power Switch
PublicationGaN power switches have better characteristics compared to the state-of-the-art Si power transistors. These devices offer high operating temperature and current densities, fast switching and low on-resistance. However, currently only a few producers offer technology of high voltage GaN transistors. Immaturity of this technology is the reason why experimental evaluation of GaN parameters must be performed to properly exploit their...
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Electrophoretic Deposition of Chitosan/Eudragit E 100/AgNPs Coatings for Controlled Release of Antibacterial Substance
PublicationThe development of bacterial infection of the tissues surrounding an implant is one of the leading causes of implant surgery failure. In order to prevent the deposition of bacteria on the implant surface and the formation of biofilm, coatings that exhibit antibacterial properties are manufactured. However, the problem is the controlled release of the therapeutic substance from the coating over the extended life of the implant [1],...
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Ladder-Based Synthesis and Design of Low-Frequency Buffer-Based CMOS Filters
PublicationBuffer-based CMOS filters are maximally simplified circuits containing as few transistors as possible. Their applications, among others, include nano to micro watt biomedical sensors that process physiological signals of frequencies from 0.01 Hz to about 3 kHz. The order of a buffer-based filter is not greater than two. Hence, to obtain higher-order filters, a cascade of second-order filters is constructed. In this paper, a more...
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Trends in Locally Balanced Energy Systems without the Use of Fossil Fuels: A Review
PublicationIn recent years, the idea of the operation of energy systems (power systems, heating systems) has changed significantly. This paper is an overview of locally balanced energy systems without the use of fossil fuels. The paper justifies the concept of local energy balancing in a new energy system that does not use fossil fuels (coal, natural gas, and crude oil), based on European Union guidelines and formal documents as well as the...