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Search results for: CAPACITOR VOLTAGE BALANCING
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Temperature influences on shear stability of a nanosize plate with piezoelectricity effect
PublicationPurpose The purpose of this paper is to predict the mechanical behavior of a piezoelectric nanoplate under shear stability by taking electric voltage into account in thermal environment. Design/methodology/approach Simplified first-order shear deformation theory has been used as a displacement field. Modified couple stress theory has been applied for considering small-size effects. An analytical solution has been taken into account...
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A new duty cycles calculation method in pulse width modulation for direct matrix converters based on the shape function concept
PublicationPaper presents a new approach to duty cycle calculation in pulse width modulation for direct matrix converters. The essence of the proposed method is the use of elementary shape function of finite element. The algorithm for calculating the duty cycles was reduced to simple operations on the coordinates of input and output voltage vectors without trigonometric functions.
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Analiza ruchowa pojazdów szynowych z uwzględnieniem zmian napięcia na odbieraku prądu
PublicationW artykule zaproponowano metodykę wykonywania analizy ruchowej pojazdów szynowych, która uwzględnia wpływ zmieniającego się napięcia zasilającego pojazd a jego właściwości ruchowe. Wykorzystując model opracowany w programie Simulink wskazano na istotne różnice w czasie przejazdu oraz w wartościach napięcia zasilającego pomiędzy proponowanym sposobem analizy a powszechnie stosowanym podejściem uproszczonym.
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NARAŻENIA NAPIĘCIOWE SILNIKÓW INDUKCYJNYCH ZASILANYCH Z FALOWNIKÓW NAPIĘCIA
PublicationW artykule przedstawiono zagadnienia związane z narażeniami izolacji silników pracujących w układach napędowych z falownikami napięcia. Znaczne stromości napięć oraz zjawiska falowe w przewodach zasilających powodują przyspieszoną degradacje izolacji maszyn. Rozwiązaniem jest stosowanie filtrów biernych na wyjściu falownika.
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Simplified Distribution Grid Modelling for Connection Analyses
PublicationThis paper considers the modelling of medium and low voltage grids for the purpose of connection studies by distribution grid operators. Possible simplifications in grid modelling are discussed, which are acceptable from the viewpoint of the final result. The main driver of the modelling simplification is the MS Excel environment used as the computation platform, and the limitation of time for grid modelling.
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REALIZACJA USŁUGI DSR NA PRZYKŁADZIE DOMÓW JEDNORODZINNYCH
PublicationW artykule przedstawiono ideę usługi DSR, czyli reakcji strony popytowej, dla odbiorców rozproszonych. Polega ona na zmniejszeniu zapotrzebowania na energię elektryczną lub przesunięcia go w czasie. Wdrożenie usługi może w znaczny sposób wpłynąć na pracę systemu elektroenergetycznego – usługa DSR może wspomóc bilansowanie systemu elektroenergetycznego, a także pozytywnie oddziaływać na jego elastyczność, wydajność oraz stabilność....
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WYDZIELONE STRUKTURY W ZDECENTRALIZOWANYM SYSTEMIE ELEKTROENERGETYCZNYM
PublicationJednym z trendów, które są obserwowane we współczesnych systemach elektroenergetycznych jest stopniowa decentralizacja, będąca w dużej mierze efektem rosnącej roli generacji rozproszonej oraz ewolucją odbiorców w stronę prosumeryzmu. Rośnie rola lokalnego bilansowania i rodzi się zapotrzebowanie na powstawanie lokalnych struktur organizacyjnych, dążących do wydzielenia części infrastruktury elektroenergetycznej. Rodzi to nie tylko...
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Electrode materials for electrochemical capacitors based on poly(3,4-ethylenedioxythiophene) and functionalized multi-walled carbon nanotubes characterized in aqueous and aprotic electrolytes
PublicationWithin this work, we report a facile one-stage synthesis of nanocomposites based on functionalized carbon nanotubes (CNTs) and electroactive polymer poly(3,4-ethylenedioxythiophene). Three different composites are investigated as potential electrode materials for the electrochemical capacitors. Two of the composites contain carbon nanotubes (ox-CNTs), functionalized by acid oxidation process (65% HNO3, 120 °C). The third composite...
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Investigation of solid polymer electrolyte gas sensor with different electrochemical techniques
PublicationIn this work solid polymer electrolyte (SPE) amperometric sulphur dioxide sensor is investigated. Nafion was used as a membrane electrode and 1M sulphuric acid as an internal electrolyte. Sensor response to sulphur dioxide was measured. Besides traditional constant voltage amperometry also different electrochemical techniques were used. Results obtained by these methods are compared.
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СИЛОВОЙ ПРЕОБРАЗОВАТЕЛЬ С АКТИВНЫМ ПОДАВЛЕНИЕМ ВЫСШИХ ГАРМОНИК ДЛЯ СИСТЕМ ЭЛЕКТРОСНАБЖЕНИЯ ЛЕТАТЕЛЬНЫХ АППАРАТОВ (Power converter with active suppression of higher harmonics for aircraft power supply systems)
PublicationПредставлены два алгоритма активной фильтрации для силового преобразователя с активным подавлением высших гармоник. Первый алгоритм основан на дискретном преобразовании Фурье: посредством синтезированной системы управления инвертированные измеренные высшие гармоники напряжения поступают на вход инвертора. Второй метод управления основан на алгоритме с использованием принципов самообучения, что значительно снижает потребность в...
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Identification of the customer meter assignment to phases in LV grid: Selected issues of UPGRID project realization
PublicationThe paper presents selected issues on the European UPGRID grant implemented by a consortium of companies from seven European states, including from Poland, on the monitoring and control of low voltage grid using measurement pre-registered data by smart AMI meters. The paper focuses on the issue of lack of information on the assignment of communal meters to individual phases.
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Proposed Amendments to Reactive Energy Billing
PublicationThis paper describes possible amendments to the rules of reactive energy billing in the tariffs in Poland. Modifications in the tariffs to improve their motivational function for distribution system users are identified as the most expedient. New problems arising from distributed generator operations are also indicated. A billing method that can be effectively implemented at the occurrence of distorted voltage and current waveforms...
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Single and Three -Phase PWM AC/AC Converters as Semiconductor Transformers
PublicationAC voltage transformation circuits contain pure or reactance PWM AC/AC converters. These circuits can be treated as AC/AC semiconductor transformers. This paper reviews single-phase and three-phase topologies: both non-isolated and isolated, single as well as two quadrant structure. Additionally, this paper present selected examples of their applications.
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A Simplified Method of Trend Removal to Determine Noise Observed During a Supercapacitor’s Discharging
PublicationIn this paper, new method of trend removal is proposed. This is a simplified method based on Empirical Mode Decomposition (EMD). The method was applied for voltage time series observed during supercapacitor discharging process. It assured the determination of an additive noise component after subtracting the identified trend component. We analyzed voltage time series observed between the terminals of the supercapacitor when discharged...
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Improved maximum power point tracking algorithms by using numerical analysis techniques for photovoltaic systems
PublicationSolar photovoltaic (PV) panels generate optimal electricity when operating at the maximum power point (MPP). This study introduces a novel MPP tracking algorithm that leverages the numerical prowess of the predictor-corrector method, tailored to accommodate voltage and current fluctuations in PV panels resulting from variable environmental factors like solar irradiation and temperature. This paper delves into the intricate dynamics...
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Ordered TiO2 nanotubes: the effect of preparation parameters on the photocatalytic activity in air purification process
PublicationVertically ordered TiO2 nanotube arrays were synthesized by anodic oxidation of titanium foil in glycerol, ethylene glycol and water-based electrolytes. The effect of electrolyte composition, anodization voltage, ultrasonic treatment and calcination time on the morphology of the resulting thin films, as well as on their photocatalytic activity in toluene removal, used as a model volatile organic compound, was investigated. Toluene,...
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Direct modulation for conventional matrix converters using analytical signals and barycentric coordinates
PublicationThis paper proposes the generalized direct modulation for Conventional Matrix Converters (CMC) using the concept of analytical signals and barycentric coordinates. The paper proposes a novel approach to the Pulse Width Modulation (PWM) duty cycle computing, which allows faster prototyping of direct control algorithms. The explanation of the new idea using analytical considerations demonstrating the principles of direct voltage...
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Risk of power cables insulation failure due to the thermal effect of solar radiation
PublicationLow-voltage, as well as high-voltage power cable lines, are usually buried in the ground. The ampacity of the power cables in the ground mainly depends on the thermal resistivity of the soil, which may vary in a wide range. A common practice in power cable systems performance is to supply them from a pole of an overhead line. If so, a section of the line is located in free air and can be directly exposed to solar radiation. In...
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MPPT and GMPPT Implementation for Buck-Boost Mode Control of quasi-Z-Source Inverter
PublicationThe focus is on the maximum power point tracking implementation for the buck-boost voltage mode control of a single-phase multilevel inverter based on a three-level neutral point clamped quasi-Z-source topology. To utilize shoot-through states only when boost function is needed and avoid it in the buck mode, two different control approaches are required. This work proposes merged control system which provides switching between...
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Problemy przyłączania farm wiatrowych do systemu elektroenergetycznego z wykorzystaniem kabli WN
PublicationArtykuł prezentuje problemy, jakie rodzi przyłączanie farm wiatrowych do systemu elektroenergetycznego za pomocą kabli wysokiego napięcia. Autor wskazuje możliwe problemy z kompensacją mocy biernej, w zależności od sposobu przyłączenia dławika kompensacyjnego i nastawień układów regulacji mocy biernej oraz napięcia farmy wiatrowej. Artykuł porusza też zagadnienia zwiększenia strat mocy czynnej powodowanych instalacją dławików kompensacyjnych.
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Novel single-stage buck-boost inverter with unfolding circuit
PublicationA novel solution of a single-stage buck-boost inverter with unfolding circuit at the output stage is presented. The inverter has a wide range of input voltage regulation, minimum passive components and a very flexible control structure. It can be applied for renewable energy systems where high power density is required. Our simulation results confirmed all theoretical statements
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Numerically Efficient Miniaturization-Oriented Optimization of an Ultra-Wideband Spline-Parameterized Antenna
PublicationDesign of ultra-wideband radiators for modern handheld applications is a challenging task that involves not only selection of an appropriate topology, but also its tuning oriented towards balancing the electrical performance and size. In this work, a low-cost design of a compact, broadband, spline-parameterized monopole antenna has been considered. The framework used for the structure design implements trust-region-based methods,...
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The Methodology of identifying the place to install shunt compensators in the transmission network
PublicationThis methodology of selection and localization of static com- paper presents pensators in wide network. Proposed method is based on analysis of voltage area power profiles in the nodes of the power grid, and designating locations, In Which Voltages ex- cessively tend to change in time. Practical way of modeling the SVC device in PLANS program you Presented, as well as some example results of research.
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Comprehensive distortion compensation of grid-connected inverter currents
PublicationThe paper presents a comprehensive approach to the compensation of phase current distortion of grid-connected power inverters. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, voltage fluctuations in the dc link, time delays in the estimation of grid voltages, and the distortion of inverter output voltages due to dead-time effects and related...
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Sensorless Control of Induction Machine Supplied by Current Source Inverter
PublicationThe paper describes the voltage control technique of induction machines supplied by a current source inverter. The control system is based on proposed new multi-scalar variables, which are named “r.” The control system contains the output filter capacitor's model. In the sensorless control system the Z type backstepping speed observer was applied. The mathematical dependences are confirmed by simulation and experimental research.
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Measurement system based on USB Z-Wave controller
PublicationA wireless measurement system based on the Z-Wave standard is presented in this paper. The system is composed of a U SB Z-Stick Gen5 controller connected to a Personal Computer and a Fibaro controller FGRGBWM-441. Operation of the system is controlled by software written in C++ using OpenZWave library. Some metrological aspects of the system are evaluated: accuracy, linearity, resolution and frequency of voltage measurements.
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Multifunctional PID Neuro-Controller for Synchronous Generator
PublicationThis paper deals with a PID Neuro-Controller (PIDNC) for synchronous generator system. The controller is based on artificial neural network and adaptive control strategy. It ensures two functions: maintaining the generator voltage at its desired value and damping electromechanical oscillations. The performance of the proposed controller is evaluated on the basis of simulation tests. A comparative study of the results obtained with...
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Interconnection of the Customer-Side Resources Using Single Phase VAPF
PublicationThe paper introduces method for utilization of the customer-side generated energy using single phase voltage active power filter. Structure and control method of the power electronics converter has been described and some simulation results are shown to prove usefulness of this arrangements. Proposed application realizes the following functions: power quality improvement, uninterruptible supplying and energy costs reduction.
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Wykorzystanie klasyfikacji funkcjonalnej usług do efektywnego zarządzania zasobami chmurowymi
PublicationWykazano jak istotnym problemem jest zarzadzanie chmurą obliczeniową, w tym alokacja zasobów do wykonania usług (workloadów) zgłoszonych przez użytkownika. Przeanalizowano problem podziału usług wdrażanych w środowiskach chmurowych na klasy określające ich funkcjonalność. Zaproponowano oryginalną metodę alokacji workloadów wykorzystującą wprowadzoną klasyfikację funkcjonalną oraz identyfikację tych klas na podstawie wielkości generowanego...
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Badania eksperymentalne transformatora hybrydowego jako kondycjonera napięcia w sieciach typu TN
PublicationArtykuł dotyczy układu dystrybucyjnego transformatora hybrydowego (DTH) przeznaczonego do zastosowania w sieciach typu TN. Opisano w nim sposoby podłączenia przewodu neutralnego do układu DTH. W dalszej części artykuł zawiera opis skonstruowanego modelu laboratoryjnego o mocy 16 kVA wraz z zastosowanym algorytmem sterowania. Ponadto przedstawiono wyniki badań eksperymentalnych, ze szczególnym uwzględnieniem oceny dokładności stabilizacji...
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Kompleksowa analiza symulacyjna układu napędowego zespołu trakcyjnego
PublicationThe paper describes an approach to comprehensive analysis of traction electric drive. The drivetrain of ED-74 electric unit equipped with four inverter-fed induction motors was modeled in Matlab/Simulink. The model consists of functional blocks as: motors, inverters, drive controllers, filters. Structure and operation of the model was described. Chosen simulation results were presented and discussed. Two methods of modeling the...
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Estimation of DC motor parameters using a simple CMOS camera
PublicationDifferent components of control systems for mobile robots are based on dynamic models. In low-cost solutions such a robot is wheeled and equipped with DC motors, which have to be included in the model of the robot. The model is fairly simple but determination of its parameters needs not to be easy. For instance, DC motor parameters are typically identified indirectly using suitable measurements, concerning engine voltage, current,...
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Frequency Diagnostics of Transformer Insulating Parameters
PublicationIn the article is presented experimental analysis and diagnostics of insulating system oil-paper for power transformers, mainly by progressive frequency method – dielectric spectroscopy. In the 1-st part of the article is described base theory about measurement and diagnostics insulating part (oil and paper) of power transformers. In the 2-nd part of article is described measuring method of insulating frequency diagnostics - frequency...
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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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Modelling of Graphene Field-Effect Transistor for lectronic sensing applications
PublicationA top-gated Graphene Field-Effect Transistor (GFET) suitable for electronic sensing applications was modelled. The applied simulation method reproduces correctly the output transfer GFET characteristics and allows to investigate doping effect caused by different physical, chemical or biological factors. The appearance of additional charge in the system results in the shift of the current-voltage characteristic. This feature could...
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Calculations of Short-Circuit Current Flows in Earth Wires of HV Lines
PublicationThis paper presents a method which enables calculating flows of short-circuit currents in earth wires of high voltage transmission lines, and its implementation in the form of a computer programme. The algorithm enables performing calculations for a double-fed line and starconnected lines (three terminal lines). The developed programme enables verifying dimensioning of earth wires in the context of their short-circuit thermal withstand...
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Electrohydrodynamic flow patterns and collection efficiency in narrow wire-cylinder type electrostatic precipitator
PublicationRecently, narrow electrostatic precipitators (ESPs) have become a subject of interest because of their possible application for the cleaning of the exhaust gases emitted by diesel engines. Diesel engines emit fine particles, which are harmful to human and animal health. There are several methods for decrease particulate emission from a diesel engines, but up to now, these methods are not enough effective or very expensive. Therefore,...
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Metoda analizy wielokryterialnej do planowania rozwoju sieci elektroenergetycznej średniego i niskiego napięcia
PublicationW artykule przedstawiono metodę wspomagającą decyzje w zakresie wyboru wariantu przyłączenia odbioru do sieci elektroenergetycznej dystrybucyjnej niskiego napięcia lub średniego napięcia oraz mikrogeneracji do sieci niskiego napięcia. Metodę tą zaimplementowano w skoroszycie kalkulacyjnym Microsoft Excel i zastosowano do analizy złożonych przypadków przyłączenia odbioru lub mikrogeneracji.
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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...
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Calculation of Induced Sheath Voltages in Power Cables – Single Circuit System versus Double Circuit System
PublicationThis paper presents comparison of values of induced sheath voltages in power cable metallic sheaths when one or two cables per phase are used. Calculation of voltages is performed for various phase sequences of the power cables. Three types of the sheaths bonding and earthing are considered. Shock hazard and voltage stress of non-metallic outer sheath of cables are evaluated. The proposed, optimal configuration of the power cable...
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A method of self-testing of an analog circuit terminated by an ADC in electronic embedded systems controlled by microcontrollers
PublicationA new self-testing method of analog parts terminated by an ADC in electronic embedded systems controlled by microcontrollers is presented. It is based on a new fault diagnosis method based on on-line (i.e. during measurement), transformations of voltage samples of the time response of a tested part to a square pulse - onto localization curves placed in the measurement space. The method can be used for fault detection and single...
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A compact smart sensor based on a neural classifier for objects modeled by Beaunier's model
PublicationA new solution of a smart microcontroller sensor based on a simple direct sensor-microcontroller interface for technical objects modeled by two-terminal networks and by the Beaunier’s model of anticorrosion coating is proposed. The tested object is stimulated by a square pulse and its time voltage response is sampled four times by the internal ADC of microcontroller. A neural classifier based on measurement data classifies the...
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Novel Family of Single-Phase Modified Impedance-Source Buck-Boost Multilevel Inverters With Reduced Switch Count
Publicationhis paper describes novel single-phase solutions with increased inverter voltage levels derived by means of a nonstandard inverter configuration and impedance source networks. Operation principles based on special modulation techniques are presented. Detailed component design guidelines along with simulation and experimental verification are also provided. Possible application fields are discussed, as well as advantages and disadvantages....
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Optimal Multivariable Control for Modified Z-source Based IPT
PublicationThis paper describes Z-source based inductive power transfer topologies control approaches. The goal of this work is a multi-variable control approach which involves a constant voltage/constant current control along with an optimal frequency control to obtain maximum efficiency. This control is applied to the wireless power transfer system based on a modified Z-source topology. The description of the control method along with simulation...
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Modified Inductive Multi-Coil Wireless Power Transfer Approach Based On Z-Source Network
PublicationThis article presents a non-conventional approach to a multi-coil wireless power transfer system based on a Z-source network. The novelty of the approach lies in the use of a Z-source as a voltage source for energy transmission through the wireless power transfer coils. The main advantage is in a reduced number of semiconductors. This paper provides the design approach, simulation and experimental study. Feasibility and possible...
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Nonlinear electrical properties of glass-ceramics nanocomposites containing ferroelectric nanocrystallites of Bi2VO5.5
PublicationNonlinear A.C. impedance measurements were conducted in the 50BiV-50SrBAlO nanocomposite as a function of frequency, temperature and A.C. voltage. This material is ferroelectric below temperature of 730 K, and above 730 K is a good ion-conductor. For this nanocomposite a low A.C. voltage of 1 V rms is enough to observe high nonlinearities. The origin of these nonlinear effects depends on the temperature and frequency. In the high...
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Modeling of Common Mode Currents Induced by Motor Cable in Converter Fed AC Motor Drives
PublicationInvestigation of conducted EMI generation in AC motor fed by pulse width modulated frequency converters requires to consider parasitic capacitances in converters, motor windings and feeding cables to be taken into account. Motor voltage transients and related common mode currents are significantly correlated with resonance effects occurring in load circuits. An analysis of frequency converter load impedance-frequency characteristics...
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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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Mikropompa elektrohydrodynamiczna na ciecz dielektryczną zasilana napięciem stałym
PublicationW niniejszym artykule zaprezentowano projekt i działanie miniaturowej pompy elektrohydrodynamicznej (EHD) zasilanej napięciem stałym przeznaczonej do chłodzenia elementów elektronicznych. Zmierzono natężenie przepływu cieczy oraz ciśnienie wytwarzane przez pracującą mikropompę. Maksymalne natężenie przepływu, 0,5 ml/min, uzyskano dla napięcia 12 kV. Zmierzone ciśnienie wyniosło 500 Pa przy przyłożonym napięciu 6 kV. Maksymalny...
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Evaluation of organic coatings condition with AFM-based method
PublicationThe paper presents an atomic force microscopy (AFM)-based approach to evaluation of local protective properties of organic coatings. Apart from topography, it provides local ac and dc characteristics of examined coating. The method consists in application of ac voltage perturbation signal between conductive AFM tip and coated metal substrate. The resulting current is used to determine local impedance characteristics. Both impedance...