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Search results for: DC MEASURMENTS
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Compatible DC and small-signal MOSFET models for radio and microwave frequency simulation
PublicationZaprezentowano nowy model stałoprądowy tranzystora MOS i kompatybilny z nim uogólniony nie-quasi-statyczny model małosygnałowy. Model stałoprądowy został eksperymentalnie zweryfikowany dla tranzystorów MOS o długości kanału od 75 nm do kilkunastu mikrometrów, a model małosygnałowy od zera herców do 30 GHz.
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High Frequency Harmonics Emission of Modern Power Electronic AC-DC Converters
PublicationModern AC/DC converters with bidirectional power flow employing PWM boost topology generate harmonic distortions of input current in relatively high frequency range tightly related to modulation carrier frequency. These frequencies and its multiples in typical applications are usually located in frequency range from single up to several of kHz. Increased harmonic emission in this frequency range can easily and harmfully influence...
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APPLICATION OF INFRARED THERMOGRAPHY TO NON-CONTACT TESTING OF AD/DC POWER SUPPLY
PublicationTesting of AC/DC power supplies using the thermography was carried out in order to assess their assembly and operation correctness before launching them on the market. The investigation was carried out for 17 AC/DC power supplies which passed the standard tests (measurements of their basic parameters and characteristics). The investigation consisted of two steps. In the first step the dispersion of temperature on power supply boards...
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Key activities to improve energy management in DC microgrids connected by urban traction
PublicationDC MicroGrids must have Energy Management Systems to guarantee efficient, dependable, and environmentally friendly electricity. The application of Model Predictive Control, proved to be helpful due to its adaptability and capacity to use non-linear models. This paper, based on an extensive literature review, identifies and discusses the three key activities to improve the characteristics of DC MicroGrids, i.e.: the use of Energy...
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Journal of Measurements in Engineering
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FLOW MEASUREMENT AND INSTRUMENTATION
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EDUCATIONAL AND PSYCHOLOGICAL MEASUREMENT
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Journal of Nursing Measurement
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Journal of Applied Measurement
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Modelling, Measurement and Control A
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Performance Measurement and Metrics
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APPLIED PSYCHOLOGICAL MEASUREMENT
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Journal of Educational Measurement
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Applied Measurement in Education
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Reducing common mode voltage and bearing currents in quasi - resonant DC - link inverter
PublicationIn the paper, a concept of separation of an inverter-fed induction motor drive from its mains supply by two transistor switches inserted in the dc-link circuit is reexamined based on the proposed parallel quasi-resonant dc-link inverter (PQRDCLI). The objective of the paper is to show an advantage of the proposed topology in limiting high frequency common mode voltage and bearing currents. In the laboratory setup, an induction...
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Four level inverter's DC bus voltage balancing with 3-terminal DAB converter
Publication—Multilevel inverters become more and more popular, especially in the medium or high voltage and high power applications. Unfortunately, some of inverter topologies require additional DC bus voltage balancing systems. This paper presents a novel approach to such systems, which is based on a multiple terminal DAB converter. Along with the voltage balancing function the proposed solution enables the connection of energy storage devices...
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Dwukierunkowy przekształtnik 4L-DC z aktywną regulacją napięć w obwodzie pośredniczącym
PublicationW artykule opisano model laboratoryjny i wyniki badań dwukierunkowego symetrycznego (ang. Back-to-Back) przekształtnika 4L-DC (ang. Four Level Diode Clamped) z dwukierunkowym dwustopniowym przetwarzaniem energii (połączenie typu ang. Back-To-Back). W celu równoważenia i regulacji napięć kondensatorów w obwodzie pośredniczącym układu zastosowano dwa trójpoziomowe przerywacze DC-DC sterowane synchronicznie metodą modulacji PO-PWM...
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The Evaluation of Expanded Uncertainty of DC Voltages in the Presence of Electromagnetic Interferences using the LabVIEW Environment
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Analysis of electromagnetic disturbances in DC network of grid connected building-integrated photovoltaic system
PublicationThis paper focuses on conducted electromagnetic interference (EMI) emissions and propagation in the DC network of grid connected building integrated photovoltaic (PV) system. The investigated PV system, consists of ten solar panels, cabling and the grid-connected one phase inverter. The EMI simulation model of the real PV system has been developed with the aid of impedance analyzer measurements of solar panels and the DC network...
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Quasi-resonant DC-link voltage inverter with enhanced zero-voltage switching control
PublicationA new topology modification of the parallel quasi-resonant circuit for a dc-link voltage inverter enables regulation of the zero voltage dc-link subperiods and the dc-link voltage gradient settings. The proposed circuit is based on four MOSFET switches with free-wheeling diodes for controlled quasi-resonant recharging between L-C tank in order to assure inverter zero voltage switching (ZVS) conditions. Design optimization of the...
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Electrical Tree Growth Behavior Under AC and DC High Voltage in Power Cables
PublicationThis work investigates the impact of an applied AC and DC high voltage on the electrical tree behavior in extruded cross-linked polyethylene (XLPE) insulation based on simulation and experimental validation. Extensive partial discharge (PD) testing methods are being implemented for high voltage cables under AC voltage for monitoring their condition. However, these PD testing methods cannot be utilized for power cables under DC...
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Electrical safety in low-voltage DC microgrids with B-type residual current devices
PublicationResidual current devices (RCDs) are most popular devices used in low-voltage installations for protection against electric shock and fire. In cases of high risk of electric shock the application of RCDs is mandatory. Currently, the spread of local direct current (DC) microgrids is widely considered. This creates new challenges for protective systems, in particular those based on RCDs. The main purpose of the research is to test...
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Tripping of F-type RCDs for sinusoidal residual current with superimposed smooth DC component
PublicationRecent trends in green energy development make that photovoltaics and electric vehicles are applied on an increasing scale. In both photovoltaic and electric vehicle charging installations, a significant value of DC component of the earth fault current may appear, which is a challenge, in particular, for commonly used residual current devices (RCDs). This paper presents results of the laboratory test on the operation of F-type...
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Mobility measurements in oxide semiconductors
PublicationPraca zawiera wyniki badań właściwości elektrycznych, optycznych i strukturalnych cienkich warstw ito i sno2. badania wykazały, że cienkie warstwy tlenków metali wykazują rezystywność charakterystyczną dla półprzewodników. poziom transmisji światła w zakresie widzialnym pozwala zaliczyć badane warstwy do materiałów przezroczystych. badane cienkie warstwy wykonano metodą rozpylania magnetronowego.
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Speech Intelligibility Measurements in Auditorium
PublicationSpeech intelligibility was measured in Auditorium Novum on Technical University of Gdansk (seating capacity 408, volume 3300 m3). Articulation tests were conducted; STI and Early Decay Time EDT coefficients were measured. Negative noise contribution to speech intelligibility was taken into account. Subjective measurements and objective tests reveal high speech intelligibility at most seats in auditorium. Correlation was found between...
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Measurements of Subnanometer Molecular Layers
PublicationSelected methods of formation and detection of nanometer and subnanometer molecular layers were shown. Additionally, a new method of detection and measurement with subnanometer resolution of layers adsorbed or bonded to the gate dielectric of the ion selective field effect transistor (ISFET) was presented.
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Reliability of Pulse Measurements in Videoplethysmography
PublicationReliable, remote pulse rate measurement is potentially very important for medical diagnostics and screening. In this paper the Videoplethysmography was analyzed especially to verify the possible use of signals obtained for the YUV color model in order to estimate the pulse rate, to examine what is the best pulse estimation method for short video sequences and finally, to analyze how potential PPG-signals can be distinguished from...
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Measurements of relative frequency instability
PublicationFrequency constancy can be determined by the change in time for the subsequent periods. The article shows that classical the method of digital period measurement is not suitable for the measurement process. Therefore, a method using an integrating circuit is being proposed. Errors in the measurement of the given method have been analyzed.
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Optoelectronic device for hematocrit measurements
PublicationAn optoelectronic system for measurements of hematocrit level (HCT) in the whole human blood is presented. Proposed system integrates a dedicated optoelectronic sensor, a microcontroller and a small LCD display in a low cost, battery-powered, handheld device. Chosen method for determining blood hematocrit level is based on optical properties of whole blood in visible and NIR wavelength range. Measurements with the use of proposed...
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Measurements of the Hydraulic Fluids Compressibility
PublicationPerformance of the hydrostatic high-pressure drive systems is affected by the changes of working fluid’s volume. Presence of air bubbles in the fluid cause this problem to be even more serious. To study this phenomenon precise measurements of fluid’s bulk modulus are necessary. Differ-ent measurement methods are applied, but they are either limited to low pressure range or give inaccurate results. To solve the problem the new...
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Anthropological Measurements of Philosophical Research
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Ryszard Strzelecki prof. dr hab. inż.
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Four Level Diode-Clamped Back-To-Back Converter with Active DC Link Voltage Control
PublicationThis article presents the design and control of 4L-DC back-to-back converter. To solve the DC link voltage balancing problem in four-level converter a new three-level double chopper topology based on PO-PWM modulation was designed and successfully tested. Also, the paper describes two phase space vector pulse width modulation 2P-SVPWM based on the shape function of finite elements. The control structure with modified Dead-Beat...
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Chapter 1 : Supply system influence on behaviour of an elektromechanical model - four bar/dc motor
PublicationPraca opisuje zagadnienia wspólnego modelowania układu wieloczłonowego i napędu elektrycznego. Analizowanym układem mechanicznym jest płaski czworobok przegubowy. Analizowany mechanizm zamodelowano jako układ wieloczłonowy z zamkniętymi wielobokami ciał. Do wymuszenia ruchu układu wykorzystano model silnika prądu stałego. Zaproponowano kilka alternatywnych sposobów zasilania silnika. Układem referencyjnym jest źródło prądu stałego....
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Modeling and simulation of a demonstration robot fed by a modular hybrid source with the dc brushless motor drive.
PublicationPrzedstawiono model demonstracyjnego robota mobilnego wykonany w środowisku Matlab-Simulink. Robot napędzany jest przez dwa silniki bezszczotkowe prądu stałego. Hybrydowe źródło energii składa się z wodorowego ogniwa paliwowego PEMFC oraz banku superkondensatorów. Wyniki symulacji przedstawiają zapotrzebowanie na moc podczas znormalizowanego cyklu jazdy robota oraz zachowanie układu w zależności od struktury hybrydowego źródła...
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DC and AC Conductivity, Biosolubility and Thermal Properties of Mg-Doped Na2O–CaO–P2O5 Glasses
PublicationBioactive glasses have recently been extensively used to replace, regenerate, and repair hard tissues in the human body because of their ability to bond with living tissue. In this work, the effects of replacing Na2O with MgO on the electrical, biosolubility, and thermal properties of the target glass 10Na2O–60P2O5–30CaO (in mol%) were investigated. The electrical properties of the glasses were studied with the impedance spectroscopy...
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Evolution of electrohydrodynamic flow of sduspended particles in a needle-to-plate negative DC corona discharge in air
PublicationCorona discharges are used for collecting dust in electrostatic precipitators (ESPs). The dust collection is mainlyrealized by the electric forces which move the ionized dust particles to the collecting electrodes. However, the presence of coronadischarge in the space between the charging and collecting electrodes in ESPs causes also the so-called ionic wind which set the gasmolecules and dust...
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RCDs Tripping in the Range from DC to AC 50 kHz for Slowly Rising Residual Current
PublicationThe wide use of power electronic converters means that in many low-voltage systems earth fault currents containing components from DC to AC of various frequencies have to be taken into account. Due to the tendency to increase the modulation frequency in converters, components of higher frequencies may be in the order of several tens of kilohertz. Therefore, it is very important to verify the behavior of devices for protection against...
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Feasibility Study of Three-Phase Modular Converter for Dual-Purpose Application in DC and AC Microgrids
PublicationThe modern concept of a universal converter is intended as a power converter (PC) suitable for application in both dc or ac grids using the same external connectors. This novel family was recently proposed to allow easier integration of renewable energy sources and energy storage systems (ESSs), interfacing with dc/ac grids and/or loads with a minimum redundancy of power switches and passive elements. This kind of solution and...
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Feasibility Study of Three-Phase Modular Converter for Dual-Purpose Application in DC and AC Microgrids
PublicationThe modern concept of a universal converter is intended as a power converter suitable for application in both dc or ac grids using the same external connectors. This novel family was recently proposed to allow an easier integration of renewable energy sources and energy storage systems, interfacing with dc/ac grids and/or loads with a minimum redundancy of power switches and passive elements. This kind of solution and applications...
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SiC-Based Power Electronic Traction Transformer (PETT) for 3 kV DC Rail Traction
PublicationThe design of rolling stock plays a key role in the attractiveness of the rail transport. Train design must strictly meet the requirements of rail operators to ensure high quality and cost-eective services. Semiconductor power devices made from silicon carbide (SiC) have reached a level of technology enabling their widespread use in traction power converters. SiC transistors oering energy savings, quieter operation, improved reliability...
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Revisiting the Measurement of Anomie
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MEASUREMENT OF NOISE IN SUPERCAPACITORS
PublicationA developed method and measurement setup for measurement of noise generated in a supercapacitor is presented. The requirements for noise data recording are considered and correlated with working modes of supercapacitors. An example of results of low-frequency noise measurements in commercially available supercapacitors are presented. The ability of flicker noise measurements suggests that they can be used to assess quality of tested supercapacitors.
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Inertial Sensors Applications in Underwater Measurements
PublicationOver the past decades microelectromechanical systems (MEMS) researchers have demonstrated a number of microsensors for almost every possible sensing modality, including attitudes. Current MEMS inertial measurement units (IMU) come in many shapes, sizes, and costs — depending on the application, and performance required. MEMS sensors have proved and demonstrated performance exceeding those of their macroscale counterpart sensors. In...
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Methods of Tire Rolling Resistance Measurements
PublicationTire rolling resistance is one of the factors related to tire/road interaction that has important influence on road vehicles performance. Raising fuel price and increased concern related to the environmental changes result in growing interest in reduction of tire rolling resistance that influences fuel consumption, especially in free-flowing highway traffic with moderate speeds. There are several methods of tire rolling resistance measurements....
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Emissivity Measurements on Shape Memory Alloys
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Rolling resistance measurements of studded tires
PublicationW pracy przedstawiono wyniki pomiaru oporu toczenia opon kolcowanych i po usunięciu kolców na nawierzchni poroelastycznej. Badania przeprowadzono na stanowisku bębnowym Katedry Pojazdów i Maszyn Roboczych Politechniki Gdańskiej. Opony kolcowane mają o około 5% wyższy współczynnik oporu toczenia w porównaniu z oponami nie kolcowanymi.
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Hardness measurements for assessment of cavitation intensity
PublicationArtykuł opisuje możliwość zastosowania pomiarów teardości erodowanego materiału do oceny natężenia zjawiska kawitacji. Proponowana metoda zakłada, że cała energia implodujących pęcherzyków kawitacyjnych zamieniana jest na przyrost twardości warstwy wierzchniej materiału
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AC loss measurements in superconducting magnet
PublicationThis report contains ordered theoretical informations about AC loss in superconducting magnets and cables. A software program to evaluate data from AC loss measurements with V-I method was made and it is also described. Examples of measurement data and result data are shown here.
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Accuracy Analysis of Measurements in Electrochemical Biosensing
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