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Wyniki wyszukiwania dla: DC VOLTAGE BALANCING
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Identification of volatile compounds based on the electrocatalytic gas sensor responses
PublikacjaMeasured response in case of electrocatalytic gas sensors is in form of a voltamperometric characteristic. Current-voltage (I-V) response shape depends on the gas type and its concentration. Such response contains significantly more information comparing with typical electrochemical sensors, but is quite difficult to analyze. When I-V curve contains current peaks, position of such peaks can be used...
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Robust identification of quadrocopter model for control purposes
PublikacjaThe paper addresses a problem of quadrotor unmanned aerial vehicle (so-called X4-flyer or quadrocopter) utility model identification for control design purposes. To that goal the quadrotor model is assumed to be composed of two abstracted subsystems, namely a rigid body (plant) and four motors equipped with blades (actuators). The model of the former is acquired based on a well-established dynamic equations of motion while the...
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The distributed model predictive controller for the nuclear power plant turbo-generator set
PublikacjaTypically there are two main control loops with PI controllers operating at each turbo-generator set. In this paper a distributed model predictive controller DMPC, with local QDMC controllers for the turbine generator, is proposed instead of a typical PI controllers. The local QDMC controllers utilize step-response models for the controlled system components. These models parameters are determined based on the proposed black-box...
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Optical activity and electro-optic effect of l-arginine doped KDP single crystals
PublikacjaWe have used the modified polarimetric methods to study optical activity (OA) in the potassium dihydrogenphosphate (KDP) crystals doped with 0.7, 1.4 and 3.8 wt% L-arginine (L-arg) amino acid. Crystals were grown by the temperature reduction method. Small changes of the absolute eigen waves ellipticity and OA values in doped crystals were noted. We have experimentally determined the signs of OA in the [1 00] and [01 0] directions...
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Analiza rezonansowego układu emisji impulsów pola elektromagnetycznego
PublikacjaW literaturze przedmiotu są opisane właściwości emiterów impulsów pola elektromagnetycznego w postaci układów bazujących na antenach wysokonapięciowych HVR (ang. High Voltage Radiator) [2, 5]. W celu podniesienia skuteczności emisji poprzez wydłużenie czasu trwania impulsu oraz zwiększenie jego amplitudy możliwe jest zastosowanie systemów rezonansowych dostrojonych do parametrów sygnału kształtowanego w układzie formowania impulsu...
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Augmented speed control scheme of dual induction motors with mutual flux angle control loop
PublikacjaThis paper proposes an augmented speed control scheme of dual induction motors fed by a five-leg voltage source inverter (VSI) with a common/shared-leg. An additional control loop is proposed here and based on the mutual flux angle – the difference between flux angular positions of the IMs. The main purpose of this research is to minimize the energy losses in the common inverter leg by controlling the mutual flux angle, at equal...
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Control system for contactless electrical energy transfer with varying air gap
PublikacjaInductive power transfer (IPT) is a system by which electrical energy may be transmitted without electrical connection through a large air gap between coils. Systems usually considered in the literature are the ones with a constant air gap. The paper describes the analysis of IPT, which allows for supplying an electrical load in the conditions of slow, in relation to the dynamics of power supply, changes in the dimensions of the...
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Selection of optimal location and rated power of capacitor banks in distribution network using genetic algorithm
PublikacjaIn this paper, the problem of placement and rated power of capacitor banks in the Distribution Network (DN) is considered. We try to suggest the best places for installing capacitor banks and define their reactive power. The considered formulation requires the optimization of the cost of two different objectives. Therefore the use of properly multiobjective heuristic optimization methods is desirable. To solve this problem we use...
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Diffusible hydrogen management in underwater wet self-shielded flux cored arc welding
PublikacjaThis article reports the effect of underwater wet welding parameters and conditions on the diffusible hydrogen content in deposited metal for welding with a self-shielded flux cored wire. The diffusible hydrogen content in deposited metal was determined using the glycerin method according to the Plackett-Burman design determining the significance of the effect of the stick out length, welding current, arc voltage, travel speed...
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Sensorless Multiscalar Control of Five-Phase Induction Machine with Inverter Output Filter
PublikacjaThe paper presents a complete solution for speed sensorless control system for five-phase induction motor with voltage inverter, LC filter and nonlinear control of combined fundamental and third harmonic flux distribution. The control principle, also known as multiscalar control, nonlinear control or natural variables control, is based on a use of properly selected scalar variables in control feedback to linearize controlled system....
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Investigation of the temperature modulation parameters on semiconductor gas sensor response
PublikacjaIn this work we present the results of the investigation of the sensing properties of semiconductor gas sensors with a sinusoidally modulated temperature in the presence of synthetic air (SA) and three volatile air pollutants, i.e. NH3, NO2 and SO2. The measurements were performed for different average sensor heater temperatures and the amplitude of the modulation signal. In addition, the extraction of features from the sensor...
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GaN Nanowire Array for Charge Transfer in Hybrid GaN/P3HT:PC71BM Photovoltaic Heterostructure Fabricated on Silicon
PublikacjaAbstract: We demonstrate that a GaN nanowire array can be used for efficient charge transfer between the organic photovoltaic layer and silicon in a Si/GaN/P3HT:PC71BM inverted hybrid heterostructure. The band alignment of such a material combination is favorable to facilitate exciton dissociation, carrier separation and electron transport into Si. The ordered nature of the GaN array helps to mitigate the intrinsic performance...
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Properties of LiMnBO3 glasses and nanostructured glass-ceramics
PublikacjaPolycrystalline LiMnBO3 is a promising cathode material for Li-ion batteries. In this work, we investigated the thermal, structural and electrical properties of glassy and nanocrystallized materials having the same chemical composition. The original glass was obtained via a standard melt-quenching method. SEM and 7Li solid-state NMR indicate that it contains a mixture of two distinct glassy phases. The results suggest that the...
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Flicker Noise in Resistive Gas Sensors—Measurement Setups and Applications for Enhanced Gas Sensing
PublikacjaWe discuss the implementation challenges of gas sensing systems based on low-frequency noise measurements on chemoresistive sensors. Resistance fluctuations in various gas sensing materials, in a frequency range typically up to a few kHz, can enhance gas sensing by considering its intensity and the slope of power spectral density. The issues of low-frequency noise measurements in resistive gas sensors, specifically in two-dimensional...
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Sensing the onset of epoxy coating degradation with combined Raman spectroscopy/atomic force microscopy/electrochemical impedance spectroscopy
PublikacjaThe paper presents the results of investigation on epoxy resin durability upon 12-week exposure to UV radiation. The aim was early determination of the onset of epoxy degradation and for this purpose an epoxy film on steel substrate systems were periodically inspected using Raman spectroscopy, atomic force microscopy and electrochemical impedance spectroscopy. The behaviour of examined polymer could be divided into three periods: immunity,...
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AFM-assisted investigation of conformal coatings in electronics
PublikacjaPurpose – This paper aims to presents a new method of investigation of local properties of conformal coatings utilized in microelectronics. Design/methodology/approach – It is based on atomic force microscopy (AFM) technique supplemented with the ability of local electrical measurements, which apart from topography acquisition allows recording of local impedance spectra, impedance imaging and dc current mapping. Potentialities...
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Hebb–Wagner polarization method for determining the oxygen ion conductivity in barium cerate-zirconate
PublikacjaIn this work, the partial conductivity of oxygen ions in BaCe0.6Zr0.2Y0.2O3 was studied at different temperatures and water partial pressures. For this purpose, a modified DC Hebb–Wagner polarization method with an electrode blocking for protons and electrons was used. A new type of measuring cell as well as a suitable calculation model were proposed for the determination of partial oxygen ionic conductivity in materials with three...
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Modelowanie bezpiecznika rozłącznikowego w układach formowania impulsów wielkiej mocy
PublikacjaProblem modelowania bezpieczników o dużej dynamice wyłączania prądu jest zagadnieniem szeroko opisywanym w literaturze. Układy takie mogą być wykorzystane w szczególności do formowania impulsów wysokiego napięcia o wartościach rzędu setek kV, charakteryzujących się czasem trwania rzędu ułamka μs. W niniejszej pracy przedstawiono empiryczny model bezpiecznika wielotopikowego, rozszerzony w oparciu o wyniki badań eksperymentalnych.
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BEZCZUJNIKOWE STEROWANIE WOLNOOBROTOWYM SILNIKIEM PMSM Z KOMPENSACJĄ MOMENTU ZACZEPOWEGO
PublikacjaW pracy przedstawiono propozycję rozwiązania problemu bezczujnikowego sterowania wolnoobrotową maszyną synchroniczną z magnesami trwałymi PMSM. Przedstawiono silnik PMSM, który zastosowano w stanowisku badawczym. Omówiono problem występowania tętnień momentu napędowego wynikający głównie ze znacznego momentu zaczepowego. Pokazano rozwiązanie kompensujące tętnienia momentu napędowego w silniku PMSM. Przygotowano procedurę startową...
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Architects and urban planners in the face of energy transition - smart cities energy aspects in shaping building structures and cities
PublikacjaContemporary architects and urban planners are facing steadily increasing challenges. The growing problems around environmental issues, shrinking natural resources and climate action are just some of them. Currently, planning should also include balancing with all the aspects of sustainable development such as not only the environmental issues, but also social and economic ones. How to meet them in the era of energy transition...
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Detection of inter-turn faults in transformer winding using the capacitor discharge method
PublikacjaThe paper presents results of an analysis of inter-turn fault effects on the voltage and current waveforms of a capacitor discharge through transformer windings. The research was conducted in the frame of the Facility of Antiproton and Ion Research project which goal is to build a new international accelerator facility that utilizes superconducting magnets. For the sake of electrical quality assurance of the superconducting magnet...
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Modelling of Mechanical Behaviour of High-Frequency Piezoelectric Actuators Using Bouc-Wen Model
PublikacjaThe paper presents the application of a modified, symmetrical Bouc-Wen model to simulate a mechanical behaviour of high-frequency piezoelectric actuators (PAs). In order to identify parameters of the model, a two-step algorithm was utilized. In the first stage, the mechanical parameters were identified by taking into account their bilinear variability and using a square input voltage waveform. In the second step, the hysteresis...
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Computer System for Evaluation of Shock Hazard in Circuits with Non-sinusoidal Earth Currents
PublikacjaEffects of current on people are mainly considered for 50/60 Hz sinusoidal current and smooth direct current. However, modern low voltage circuits are very often equipped with power electronics converters – rectifiers, frequency converters, therefore non-sinusoidal earth currents (touch currents) occur. For non-sinusoidal currents safety criteria should be modified. This paper presents a computer system, based on LabVIEW environment,...
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Morphology and properties of nanotubular oxide layer on the Ti13Zr13Nb alloy
PublikacjaThe Ti13Zr13Nb alloy in solid and porous form was oxidised. The constant voltage 20 V, oxidation time 0.5 and 1 h, and 1 M H3PO4 (orthophosphoric acid) with addition of HF (hydrofluoric acid) as a test solution were applied. SEM (Scanning Electron Microscope) examinations of surface, EDS (Energy Dispersive X-ray Spectroscopy) chemical analysis, nanohardness and nano-scratch tests, and corrosion potentiokinetic tests at various...
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Electrophoretically Deposited Chitosan/Eudragit E 100/AgNPs Composite Coatings on Titanium Substrate as a Silver Release System
PublikacjaDue to the possibility of bacterial infections occurring around peri-implant tissues, it is necessary to provide implant coatings that release antibacterial substances. The scientific goal of this paper was to produce by electrophoretic deposition (EPD) a smart, chitosan/Eudragit E 100/silver nanoparticles (chit/EE100/AgNPs) composite coating on the surface of titanium grade 2 using different deposition parameters, such as the...
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Diagnostyka off-line stanu izolacji uzwojeń silników 6 kV z wykorzystaniem obrazowania akustycznego wyładowań niezupełnych
PublikacjaW zakładach przemysłowych, w których kluczowe procesy produkcyjne są realizowane z wykorzystaniem silników średniego napięcia, dla których diagnostyka izolacji uzwojeń ma istotne znaczenie. W tym celu wykonuje się ocenę porównawczą wyników pomiarów wyładowań niezupełnych (WNZ) wykonywanych dla jednostek tego samego typu, a jej skuteczność w znacznej mierze wynika z wieloletniego doświadczenia diagnosty. Dla opracowania wyników...
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Samotestowanie toru analogowego ze wzmacniaczem w pełni różnicowym w elektronicznych systemach wbudowanych sterowanych mikrokontrole-rami
PublikacjaPrzedstawiono 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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Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4
PublikacjaSodium-calcium-phosphate glasses doped with SiO2 or Si3N4 having similar sodium ion concentrations were prepared by melt quenching. The conductivity was measured by impedance spectroscopy under nitrogen atmosphere in a wide frequency range (10 mHz–1 MHz) and wide temperature range (153–473 K). At 36.6 °C, DC conductivities of all glasses vary between 1.1 ∗ 10−12 and 8.9 ∗ 10−12 S cm−1 and have similar activation energies (between...
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Nanostructure and dielectric behavior of vanadate glasses containing BaTiO3
PublikacjaThe ac and dc electrical conductivity of barium titanate doped bismuth-vanadate as-quenched and heat-treated materials was measured in the frequency range from 1 mHz to 1 MHz and in the temperature range from 153 K to 423 K with the impedance spectroscopy method. The microstructure was investigated by means of XRD, scanning electron microscopy (SEM), atomic force microscopy (AFM) and confocal microscopy. The obtained results showed...
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Portable exhaled breath analyzer employing fluctuation-enhanced gas sensing method in resistive gas sensors
PublikacjaThis paper presents a portable exhaled breath analyser, developed to detect selected diseases. The set-up employs resistive gas sensors: commercial MEMS sensors and prototype gas sensors made of WO3 gas sensing layers doped with various metal ingredients. The set-up can modulate the gas sensors by applying UV light to induce physical changes of the gas sensing layers. The sensors are placed in a tiny gas chamber of a volume...
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Ionic conductivity behavior by activated hopping conductivity (AHC) of barium aluminoborosilicate glass–ceramic system designed for SOFC sealing
PublikacjaNon-conducting BaO-B2O3-Al2O3-SiO2 parent glasses designed for solid oxide fuel cell (SOFC) sealing applications were prepared using the melt-quenching technique. The glass formation region was determined according to phase equilibrium relations and was found to be in the composition range 70BaO-(x)Al2O3-(10−x)B2O3-20SiO2 where 3.0 < x < 6.0 wt%. The conductivity values obtained conductivity ranged from 10−5 to 10−10 S/cm at temperatures...
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Photovoltaic Maximum Power Point Technique based on Incremental Conductance (INCON) control algorithm
PublikacjaMaximum output power status can significantly improve the deployment rate of solar energy system. In order to get the maximum power output, issue of tracking maximum power point (MPP), reduced harmonics around MPP and improve efficiency of the solar power energy system, this paper presents the improved maximum power point tracking (MPPT) control...
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Superconductivity in CaBi2
PublikacjaSuperconductivity is observed with critical temperature Tc = 2.0 K in self-flux-grown single crystals of CaBi2. This material adopts the ZrSi2 structure type with lattice parameters a = 4.696(1) Å, b = 17.081(2) Å and c = 4.611(1) Å. The crystals of CaBi2 were studied by means of magnetic susceptibility, specific heat and electrical resistivity measurements. The heat capacity jump at Tc is DC/gTc = 1.41, confirming bulk superconductivity;...
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Advanced operating methods
PublikacjaSelected operating methods of resistive gas sensors were presented. The methods utilize flicker noise (1/f noise), which gives additional information about ambient gas when compared with the recorded changes of DC resistance only. Methods of flicker noise measurements were outlined. Recently developed prototype gas sensors comprising golden nanoparticle functionalized with organic ligands can generate intense flicker noise induced...
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Falowniki napięcia z quasi-rezonansowym obwodem pośredniczącym w układach napędowych
PublikacjaW monografii przedstawiono zagadnienia związane z wykorzystaniem pośrednich przemienników częstotliwości z rezonansowymi oraz quasi-rezonansowymi obwodami pośredniczącymi w układach napędowych. Omówiono wpływ przełączania „twardego” przy niezerowych prądach i napięciach łączników na właściwości eksploatacyjne elektrycznego układu napędowego. Ponadto dokonano przeglądu wybranych topologii przekształtników DC/AC, zapewniających techniki...
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Hydroxyapatite deposition on the laser modified Ti13Nb13Zr alloy
PublikacjaThe Ti13Nb13Zr alloy was subjected to laser modification with the Nd:YAG laser provided that such treatment would increase the surface roughness followed improved adhesion of hydroxyapatite (HAp) coatings The hydroxyapatite was deposited by electrophoretic method in suspension of 0.5 g HA powder and 100 ml ethyl alcohol. The deposition was carried out for 10 min at 10 V voltage followed by drying at room temperature for 24 h and...
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Low speed permanent magnet synchronous generator for vertical axis wind turbine
PublikacjaThe paper presents design process and tests of a prototype low speed permanent magnet synchronous generator (PMSG) dedicated for the innovative vertical-axis wind turbine. The rated data of the designed generator are following: power - 15 kVA, voltage - 400 V (Y), rotation speed - 93.75 rpm. The design assumptions, chosen results of the design process and experimental tests of the prototype PMSG are presented. The considered PMSG...
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Low-frequency tripping characteristics of residual current devices
PublikacjaFast development of various types of converters makes their utilization in industry and in domestic installations very common. Due to converters, an earth fault current waveform in modern circuits can be distorted or its frequency can be different than 50/60 Hz. Frequency of earth fault (residual) current influences tripping of residual current devices which are widely used in low voltage systems. This paper presents the behaviour...
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LabVIEW-based intelligent system of protection against electric shock for photovoltaic installations
PublikacjaEvaluation of shock hazard in installations with photovoltaic sources of energy is more complicated than in a conventional low voltage system. In case of earth fault in photovoltaic generators, that are connected to the AC power public grid, a composite waveform of earth fault current in the installation may occur. For composite waveforms, the safety criteria should be modified. The paper considers the effect of the composite waveforms...
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The determinants of morphology and properties of the nanohydroxyapatite coating deposited on the Ti13Zr13Nb alloy by electrophoretic techniqe
PublikacjaThe titanium and its alloys belong at present to the most preferred and commonly applied biomaterials for load- bearing implants. The surfaces of biomaterials are subjected to modification, including the hydroxyapatite coatings deposited in order to ensure corrosion resistance and better joining between an implant and a bone through the possibility of ingrowth bone into the coating. In this paper, the morphology and properties...
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The impact of material degradation on the resistance and reliability of truss structures
PublikacjaThe paper analyses limit load-carrying capacity and buckling load of truss towers used to support high voltage power lines. The analysed typical structure was subjected to characteristic loads and their combinations. The results were applied to assess structural resistance with regard to steel corrosion in the long-term operation. The extent of structural deterioration was assessed due to Young's modulus decrement in the course...
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Induced sheath voltages in 110 kV power cables – case study
PublikacjaThis paper considers electric shock hazard due to induced sheath voltages in 110 kV power cables. The purpose of this paper is to find an optimal configuration of the power cable system, taking into account electric shock hazard and ability of the system to transfer maximal power. A computer simulations on a computer model of the local power system, comprising high voltage power cables, were carried out. This model enables to analyse...
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Low-frequency noise in ZrS3 van der Waals semiconductor nanoribbons
PublikacjaWe report the results of the investigation of low-frequency electronic noise in ZrS3 van der Waals semiconductor nanoribbons. The test structures were of the back-gated field-effect-transistor type with a normally off n-channel and an on-to-off ratio of up to four orders of magnitude. The current–voltage transfer characteristics revealed significant hysteresis owing to the presence of deep levels. The noise in ZrS3 nanoribbons...
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Advances in CSI-fed induction motor drives
PublikacjaThe application of current source inverters (CSI)in induction motor (IM) drives offers a number of advantages,including: voltage boosting capability, natural shoot-throughshort-circuit protection and generation of sinusoidal voltages.The exact generation of sinusoidal voltages is possible thanks tothanks to the effect of the output ac filter capacitors and mayimprove the accuracy of sensorless IM control. The eliminationof high...
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Selection of excitation signals for high-impedance spectroscopy
PublikacjaA 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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Modeling and Evaluation of Electric Treeing Phenomena in Polymeric Cable Insulation
PublikacjaThis paper investigates the treeing phenomenon in polymeric materials such as crosslinked polyethylene (XLPE) that is widely used in medium and high voltage power cables as primary insulation. The modeling of electrical tree growth in the insulation from its initiation to breakdown is significant research work that illustrates the discharge dynamics and its impact on aging process in polymeric insulation. This study utilizes pulse...
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Performance of acicular grindable thermocouples for temperature measurements at sliding contacts
PublikacjaThe present study investigates the performance of acicular grindable thermocouples based on a constantan wire / steel hollow cylinder construction. The experiments showed that the measuring junction electrical resistance, temperature–voltage characteristic, measuring junction rise time and signal noise standard deviation of the acicular thermocouples are comparable to those of conventional J-type thermocouples with bare wire diameter...
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Algorytmy wyodrębniania składowych symetrycznych sygnału pomiarowego napięcia w przypadku asymetrii sieci trójfazowej
PublikacjaW artykule zaprezentowano działanie wybranych algorytmów wykorzystywanych do wyodrębniania składowych symetrycznych z sygnałów pomiarowych napięcia lub prądu w przypadku wystąpienia asymetrii trójfazowej sieci elektroenergetycznej. Weryfikacji działania algorytmów dokonano na podstawie badań symulacyjnych i laboratoryjnych w układzie w którym jako odbiornik zastosowano stojan maszyny asynchronicznej pierścieniowej. Określono wpływ...
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Nowoczesne układy przekształtników wielopoziomowych do zasilania statków z lądu
PublikacjaW 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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Li nucleation on the graphite anode under potential control in Li-ion batteries
PublikacjaApplication of Li-ion batteries in electric vehicles requires improved safety, increased lifetime and high charging rates. One of the most commonly used intercalation anode material for Li-ion batteries, graphite, is vulnerable to Li nucleation, a side reaction which competes with the intercalation process and leads to loss of reversible capacity of the battery, ageing and short-circuits. In this study, we deploy a combined grand...