Filtry
wszystkich: 778
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Wyniki wyszukiwania dla: CIRCUIT THEORY, CIRCUIT SIMULATION, TRANSMISSION LINES, FRACTIONAL CALCULUS
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On Applications of Fractional Derivatives in Circuit Theory
PublikacjaIn this paper, concepts of fractional-order (FO) derivatives are discussed from the point of view of applications in the circuit theory. The properties of FO derivatives required for the circuit-level modelling are formulated. Potential problems related to the generalization of transmission line equations with the use of FO derivatives are presented. It is demonstrated that some of formulations of the FO derivatives have limited...
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Simulation of Signal Propagation Along Fractional-Order Transmission Lines
PublikacjaIn this paper, the simulation method of signal propagation along fractional-order (FO) transmission lines is presented. Initially, fractional calculus and the model of FO transmission line are introduced. Then, the algorithm allowing for simulation of the nonmonochromatic wave propagation along FO transmission lines is presented. It employs computations in the frequency domain, i.e., an analytical excitation is transformed to the...
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On Applications of Elements Modelled by Fractional Derivatives in Circuit Theory
PublikacjaIn this paper, concepts of fractional-order (FO) derivatives are reviewed and discussed with regard to element models applied in the circuit theory. The properties of FO derivatives required for the circuit-level modeling are formulated. Potential problems related to the generalization of transmission-line equations with the use of FO derivatives are presented. It is demonstrated that some formulations of FO derivatives have limited...
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Calculations of Short-Circuit Current Flows in Earth Wires of HV Lines
PublikacjaThis 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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Selection of circuit geometry for miniaturized microwave components based on concurrent optimization of performance and layout area
PublikacjaThe paper presents a framework for automated EM-driven circuit geometry selection of miniaturized microwave components. Selection of a particular layout is based directly on miniaturization rates achieved for a set of candidate circuit geometries. Size reduction of the considered structures is obtained by replacing their main building blocks (i.e., conventional transmission lines) with slow-wave composite cells and meander lines....
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EHV transmission lines wires location on line operation issues - case studies
PublikacjaTransmission 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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Case studies of resonance phenomena in high voltage overhead power lines with shunt reactors
PublikacjaMisguided design of the towers of power transmission lines can lead to serious problems such as voltage asymmetry, overvoltages, electric arc extinction difficulties or resonance – in case of double circuit line with shunt reactors. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors.
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Surrogate-assisted EM-driven miniaturization of wideband microwave couplers by means of co-simulation low-fidelity models
PublikacjaThis article proposes a methodology for rapid design optimization of miniaturized wideband couplers. More specifically, a class of circuits is considered, in which conventional transmission lines are replaced by their abbreviated counterparts referred to as slow-wave compact cells. Our focus is on explicit reduction of the structure size as well as on reducing the CPU cost of the design process. For the sake of computational feasibility,...
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Secondary arc modelling for single pole reclosing analyses
PublikacjaThe paper discusses two evaluation methods of single pole auto-reclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage calculation results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc model implementation is presented. The paper presents the study results for the three types of EHV transmission...
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Earth wires currents calculation by tableau analysis
PublikacjaThe paper presents a new method to compute a phase-to-earth fault current distribution in overhead transmission line. The method is based on the tableau analysis of an unbalanced, multi-wire model of a transmission line. It allows for the calculation of current distribution in overhead earth wires along the transmission line. Additionally, it may be used to calculate currents in a tower’s earthing system as well as voltages over...
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Expedited Geometry Scaling of Compact Microwave Passives by Means of Inverse Surrogate Modeling
PublikacjaIn this paper, the problem of geometry scaling of compact microwave structures is investigated. As opposed to conventional structures (i.e., constructed using uniform transmission lines), re-design of miniaturized circuits (e.g., implemented with artificial transmission lines, ATSs) for different operating frequencies is far from being straightforward due to considerable cross-couplings between the circuit components. Here, we...
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A structure and design optimization of novel compact microscrip dual-band rat-race coupler with enhanced bandwidth
PublikacjaIn the letter, a topology of a novel compact wideband dual-band rat-race coupler has been presented along with its computationally efficient design optimization procedure. Reduction of the circuit size has been achieved by meandering transmission lines of the conventional circuit. At the same time, the number of independent geometry parameters has been increased so as to secure sufficient flexibility of the circuit, necessary in...
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Inline Microstrip Bandpass Filter With Two Transmission Zeros and Increased Order Using Spurious Resonance of Frequency-Dependent Inverter
PublikacjaA design method for a class of fourth-order inline microstrip bandpass filter with two transmission zeros and 20% fractional bandwidth is presented. The filter consists of two quarter-wavelength transmission-line resonators coupled by a frequency-dependent inverter. The inverter is composed of two open-ended stubs that are connected by an interdigital capacitor and introduces two poles and two transmission zeros in the filter response....
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Design of a compact planar transmission line for miniaturized rat-race coupler with harmonics suppression
PublikacjaThis paper presents an elegant yet straightforward design procedure for a compact rat-race coupler (RRC) with an extended harmonic suppression. The coupler’s conventional λ/4 transmission lines (TLs) are replaced by a specialized TL that offers significant size reduction and harmonic elimination capabilities in the proposed approach. The design procedure is verified through the theoretical, circuit, and electromagnetic (EM) analyses,...
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Rapid Design Tuning of Miniaturized Rat-Race Couplers Using Regression-Based Equivalent Network Surrogates
PublikacjaA simple technique for fast design tuning of compact rat-race couplers is presented. Our approach involves equivalent circuit representation, corrected by nonlinear functions of frequency with coefficients extracted through nonlinear regression. At the same time, the tuning process connects two levels of coupler representation: EM simulation of the entire circuit and re-optimization of the coupler building blocks (slow-wave cells...
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On Design Optimization of Miniaturized Microscrip Dual-Band Rat-Race Coupler with Enhanced Bandwidth
PublikacjaIn the paper, a novel topology of a miniaturized wideband dual-band rat-race coupler has been presented. Small size of the circuit has been obtained by meandering transmission lines of the conventional circuit. At the same time, the number of independent geometry parameters has been increased in order to secure sufficient circuit flexibility in the context of its design optimization for dual-band operation. Optimum dimensions of...
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Electromagnetic-based derivation of fractional-order circuit theory
PublikacjaIn this paper, foundations of the fractional-order circuit theory are revisited. Although many papers have been devoted to fractional-order modelling of electrical circuits, there are relatively few foundations for such an approach. Therefore, we derive fractional-order lumped-element equations for capacitors, inductors and resistors, as well as Kirchhoff’s voltage and current laws using quasi-static approximations of fractional-order...
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Miniaturized dual‐band branch‐line coupler with enhanced bandwidth
PublikacjaIn this letter, a miniaturized hybrid dual-band branch-line coupler (BLC) with enhanced fractional bandwidths is proposed. Compact size and bandwidth enhancement are obtained using meandered transmission line sections with broken symmetry between cross-coupling branches. The circuit is designed at a low numerical cost using surrogate-assisted techniques. The optimized design features small size of only 0.25λg×0.19λg(28% miniaturization...
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Novel structure and EM-driven design of miniaturized microstrip rat-race coupler
PublikacjaIn this paper, a novel structure and design procedure of a miniaturized microstrip rat-race coupler (RRC) is described. Small size of the RRC is achieved by folding the transmission lines of the conventional circuit into its interior, as well as by implementation of the structure on three layers. The final size of the coupler realized for the operating frequency of 1 GHz is only 220 mm2, which gives over 95% footprint reduction...
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Nonlinear secondary arc model use for evaluation of single pole auto-reclosing effectiveness
PublikacjaPurpose – The purpose of this paper is to discuss two evaluation methods of single pole autoreclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc implementation is presented. Design/methodology/approach – A computer simulation studies were...
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The contactless method of chip-to-chip high-speed data transmission monitoring
PublikacjaThis paper presents a technique of decoupling differential signals transmitted in a pair of microstrip lines on a printed circuit board (PCB), using dedicated coupler for high speed data transmission monitoring in chip-to-chip interconnections. The coupler used for signal probing is overlayed on the pair of microstrip lines under test, and provides a signal to the next blocks of the measurement system without disturbing transmission...
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Computer-Aided Calculations of Earth Potential Rise in High Voltage Overhead Lines
PublikacjaHigh 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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Fractional Order Circuit Elements Derived from Electromagnetism
PublikacjaIn this paper, derivations of fractional-order (FO) circuit-element equations from electromagnetism are presented. Whilst many papers are devoted to FO modelling of electrical circuits, there are no strong foundations for such an approach. Therefore, we investigate relations between the FO electromagnetism and the FO circuit theory. Our derivations start from quasi-static (QS) approximations of Maxwell's equations in media with...
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Magnetic and capacitive couplings influence on power losses in double circuit high voltage overhead transmission line
PublikacjaPurpose – The paper aims to discuss problems of power and energy losses in a double-circuit overhead transmission line. It was observed from energymeters’ readings, that in such a line, active power losses can be measured as “negative”. The “negative” active power losses appear when the active power injected to the circuit is lower than the active power received at the circuit end. The purpose of this paper is to explain this phenomenon. Theoretical...
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A Circuital Model of Electric Arc in a Circuit Breaker
PublikacjaThe paper presents a circuital model of arc in a circuit breaker. The model is intended to be used in simulations of the electric circuits transients. It was implemented in the ATP simulation program. The article presents also a few simulation examples of simple DC and AC circuit containing described arc model.
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Magnetic and capacitive couplings influence on power and energy measurement in double circuit high voltage overhead transmission line
PublikacjaThe paper discusses influence of magnetic and capacitive couplings on power and energy measurement in case of double circuit high voltage overhead transmission line. There are presented and discussed various factors influencing the power flow among the line‟s circuits. Mathematical model based calculations results are compared to the real transmission line measurements.
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Resonance problems in UHV transmission lines
PublikacjaThe paper presents resonance phenomena observed in 400 kV transmission lines in the Polish power system. Two events are analysed, when shunt reactors used for reactive power compensation, caused overvoltages and overcurrent protection tripping as a result of resonance. An oscillographic fault recordings from protection devices are compared to time domain simulation results. The obtained simulation results match fault recordings,...
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Non-linear circuit model of a single doubly-fed induction machine formulated in natural axes for drive systems simulation purposes
PublikacjaMathematical modelling and a circuit model formulated in natural axes of a single doubly-fed induction machine, with the account of magnetic circuit nonlinearity are presented in the paper. Derivation of the model differential equations was based on Lagrange's energy method. State functions of magnetic elements in the model are non-linear and depend on all currents flowing in the machine windings and on the angle of rotor position....
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Conducted emi identification in power electronic converters : modeling of EMI generation and propagation using circuit simulation and wiener filtering methods.
PublikacjaThis work presents the circuit simulations and the conventional signal processing technique (Wiener filtering) in order to reconstruct conducted ElectroMagnetic Interferences (EMI), generated and propagated in power electronics converters. In the simulation study, the most accurate presently available models of components of circuit have been used and improved. The proposed Wiener filtering method allows to identifying the transfer...
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Magnetic Field Generated by Short Circuit Current in the 110 kV Power System
PublikacjaElectric fields within tissues induced by magnetic fields including transients or short-term peaks should not be time averaged and be regarded as instantaneous values as established in the ICNIRP (International Commission on Non - Ionizing Radiation Protection) guidelines. Measurements of power lines magnetic fields with regard to human beings exposure are carried out typically with maximum current load at current balance condition...
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Capacitively coupled ECG measurements - a CMRR circuit improvement
PublikacjaA typical galvanic-connected electrocardiogram (ECG) measurement system utilizes two signal’s electrodes and a third one in driven-right-leg (DRL) circuit for improving a common-mode rejection ratio(CMRR) of the acquisition system. In capacitive-coupled ECG similar techniques are used, however it is expected, that the utilized DRL subsystem is formed using a capacitive coupling approach, too. An improvement of the acquisition system...
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Novel single-stage buck-boost inverter with unfolding circuit
PublikacjaA 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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The Issues of Reactive Power Compensation in High-voltage Transmission Lines
PublikacjaThis paper discusses the selection of compensation shunt reactors for a double-circuit 400 kV transmission line using the example of the newly built Elk Bis – Alytus transmission line. The analysis takes into account various conditions of the power system. The published results relate to voltage levels in steady states and during switching processes and short circuits.
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On Applications of Fractional Derivatives in Electromagnetic Theory
PublikacjaIn this paper, concepts of fractional-order (FO) derivatives are analysed from the point of view of applications in the electromagnetic theory. The mathematical problems related to the FO generalization of Maxwell's equations are investigated. The most popular formulations of the fractional derivatives, i.e., Riemann-Liouville, Caputo, Grünwald-Letnikov and Marchaud definitions, are considered. Properties of these derivatives are...
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Automatic tuning of a resonant circuit in wireless power supply systems for biomedical sensors
PublikacjaIn this paper, a tuning method of a resonant circuit suited for wireless powering of miniature endoscopic capsules is presented and discussed. The method allows for an automatic tuning of the resonant frequency and matching impedance of a full wave rectifier loading the resonant circuit. Thereby, the receiver tunes so as to obtain the highest power efficiency under given conditions of transmission. A prototype receiver for wireless...
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Simulation of Wave Propagation in Media Described by Fractional-Order Models
PublikacjaIn this paper, algorithms for simulation of the wave propagation in electromagnetic media described by fractional-order (FO) models (FOMs) are presented. Initially, fractional calculus and FO Maxwell's equations are introduced. The problem of the wave propagation is formulated for media described by FOMs. Then, algorithms for simulation of the non-monochromatic wave propagation are presented which employ computations in the time...
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A spice equivalent circuit for modeling the performance of dual frequency echo-sounder
PublikacjaThe paper presents novel network equivalent circuit of piezoceramic circular disc transducers that takes into account thickness and radial 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. The approximate solution for harmonic case is represented in the form of 4x4 matrix, which is synthesised and...
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Some applications of fractional order calculus
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Naval mine detection system based of FPGA circuit
PublikacjaElectrochemical processes take place in a metal object immersed into sea water even if an anticorrosive coating is applied [1]. As a result, flowing field appears around the object. There are naval mines between many other objects situated in the sea. Naval mines can be put in the seabed in order to be more difficult to detect by sonars. Such a mine is located on the line demarking two environments of different electrical conductivity....
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Determination of equivalent circuit parameters of an induction motor using field calculation software
PublikacjaSimulation of the drive system comprising a power electronic converter and an induction motor requires that the equivalent circuit parameters of the motor are known. These parameters can be either measured or calculated. A method of calculation of self and mutual inductances that are parameters of a polyphase model of the motor is presented in the paper. All self-inductances and mutual inductances have been calculated using the...
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Certified Integrated Circuit Design Lab - obtaining the certificate and the benefits of having it
PublikacjaThis paper describes the process of establishing and maintaining a certified integrated circuit design lab. The advantages of having a certification for the lab are presented, and also how to obtain the certificate based on the example of Cadence Certified Lab at Gdansk University of Technology, Poland. Various integrated circuits designed at the lab are also briefly shown.
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A New, Reconfigurable Circuit Offering Functionality of AND and OR Logic Gates for Use in Algorithms Implemented in Hardware
PublikacjaThe paper presents a programmable (using a 1-bit signal) digital gate that can operate in one of two OR or AND modes. A circuit of this type can also be implemented using conventional logic gates. However, in the case of the proposed circuit, compared to conventional solutions, the advantage is a much smaller number of transistors necessary for its implementation. Circuit is also much faster than its conventional counterpart. The...
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Zero-Pole Approach in Microwave Passive Circuit Design
PublikacjaIn this thesis, optimization strategies for design of microwave passive structures including filters, couplers, antenna and impedance transformer and construction of various surroogate models utilized to fasten the design proces have been discussed. Direct and hybrid optimization methodologies including space mapping and multilevel algorithms combined with various surrogate models at different levels of fidelity have been utilized...
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Representation of magnetic hysteresis in single-phase transformer for circuit simulations
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. In the circuit transformer model, it is assumed that there is a flux common Φ to all windings as nonlinear and hysteretic function of the total currents Θ (Ampere turns) of all windings. To simulate magnetic behaviour of the iron core the feedback scalar Preisach model of hysteresis is developed. The Preisach...
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Structural Health Monitoring of Overhead Power Transmission Lines
PublikacjaStructural Health Monitoring (SHM) is a novel and continuously developing branch of science and technology that draws attention of scientists all over the world. It creates opportunities to detect, localize and identify structural damage of various types such as: line breakage, permissible sag, bolt loosening, fatigue cracking or insulator contamination. On the other hand the methods used to estimate the remaining operational...
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Thermal and Electrodynamic Risk of Residual Current Devices in the Case of Back-Up Protection by Overcurrent Circuit Breakers
PublikacjaResidual current operated circuit breakers without integral overcurrent protection should be back-up protected. As back-up protection devices, overcurrent circuit breakers are used. The maximum let-through energy and let-through current of the overcurrent devices were evaluated under laboratory conditions. The thermal and electrodynamic risk of residual current devices was analyzed.
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Impedance Measurement and Selection of Electrochemical Equivalent Circuit of a Working PEM Fuel Cell Cathode
PublikacjaThe dynamic impedance analysis of direct methanolfuel cell (DMFC) cathode supplied with pure oxygen is pre-sented. Presented results were obtained during dynamic chang-es of the current density in working fuel cell. Investigation ofthe occurring processes at cathode was carried with dynamicelectrochemical impedance spectroscopy (DEIS). A discussionwas conducted based on the determined correlation parameterχ2. It was shown that...
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Calculation of Induced Sheath Voltages in Power Cables – Single Circuit System versus Double Circuit System
PublikacjaThis 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 LUMPED-CIRCUIT MODEL OF CIRCULAR PISTON TRANSDUCER FOR MODELING ITS PERFORMANCE IN DUAL FREQUENCY OPERATING MODES
PublikacjaThe 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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Modeling of Electrodynamic Phenomena in an Ultra-Rapid Inductive–Dynamic Actuator as Applied to Hybrid Short-Circuit Breakers - A Review Study
PublikacjaThis article is a study of the research development of electrodynamic phenomena occurring in ultra-fast electrodynamic drives. These types of linear drives are among the fastest, not only because of the huge accelerations achieved, but, above all, because of the extremely short reaction time. For this reason, electrodynamic drives are used in hybrid short-circuit breakers. The phenomena occurring in this type of drive are actually...
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Modelling heat transfer in heterogeneous media using fractional calculus
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Modeling Heat Transfer in Heterogeneous Media Using Fractional Calculus
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Transmission protocol simulation framework for the resource-constrained sensor network
PublikacjaIn this paper the simulation framework for simulation of the sensor network protocol is presented. The framework enables the simultaneous development of the sensor network software and the protocol for the wireless data transmission. The advantage of using the framework is the convergence of the simulation with the real software, because the same software is used in real sensor network nodes and in the simulation framework. The...
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A measurement method for lossy capacitive relative humidity sensors based on a direct sensor-to-microcontroller interface circuit
PublikacjaA 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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DIGITAL HYDRAULICS CIRCUIT BASED ON PWM FUNCTION FOR CONTROLLING HYDRAULIC ACTUATOR POSITION
PublikacjaHydraulic systems are used in many different industries, such as multi-source hydrostatic drive systems. In traditional hydraulic systems, a proportional servo valve is used to control the position of hydraulic actuators. The low energy efficiency and high cost of these control valves are two major problems with these systems. Digital hydraulics is one of the most unique ideas on how to solve these problems. Researchers like digital...
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Application of Closed Circuit Television for Highway Telematics
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A metrological analysis of the input circuit of an impedance meter.
PublikacjaW pracy przeprowadzono analizę obwodu wejściowego miernika impedancji W analizie obwodu wejściowego, uwzględniono najważniejsze czynniki wpływające na sygnały na jego wejściu: parametry zmiennoprądowe zastosowanych wzmacniaczy, rezystancję zakresową przetwornika prąd-napięcie, pojemności montażowe. Przeprowadzono symulację sygnałów wydzielanych w obwodzie dla różnych wartości pojemności pasożytniczych, następnie dokonano badań...
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Transmission Protocol Simulation Framework For The Resource-Constrained Wireless Sensor Network
PublikacjaIn this paper a prototype framework for simulation of wireless sensor network and its protocols are presented. The framework simulates operation of a sensor network with data transmission, which enables simultaneous development of the sensor network software, its hardware and the protocols for wireless data transmission. An advantage of using the framework is converging simulation with the real software. Instead of creating...
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Neural Approximators for Variable-Order Fractional Calculus Operators (VO-FC)
PublikacjaThe paper presents research on the approximation of variable-order fractional operators by recurrent neural networks. The research focuses on two basic variable-order fractional operators, i.e., integrator and differentiator. The study includes variations of the order of each fractional operator. The recurrent neural network architecture based on GRU (Gated Recurrent Unit) cells functioned as a neural approximation for selected...
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The influence of dynamic load changes on temporary impedance in hydrogen fuel cells, selection and validation of the electrical equivalent circuit
PublikacjaTo achieve optimal performance of a fuel cell, a reliable monitoring and diagnostic method is required. The currently utilized methods give limited information or they are impossible to use under dynamic working conditions. To obtain comprehensive information about the fuel cell operation we utilized novel dynamic electrochemical impedance spectroscopy. Impedance measurements in dynamic mode were performed on a hydrogen fuel cell,...
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A novel dual-band rectifier circuit with enhanced bandwidth for RF energy harvesting applications
PublikacjaIn recent years, a rapid development of low-power sensor networks, enabling machine-to-machine communication in applications such as environmental monitoring, has been observed. Contemporary sensors are normally supplied by an external power source, typically in a form of a battery, which limits their lifespan and increases the maintenance costs. This problem can be addressed by harvesting and converting ambient RF energy into...
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A measurement method for capacitive sensors based on a versatile direct sensor-to-microcontroller interface circuit
PublikacjaIn the paper, there is presented a new time-domain measurement method for determining the capacitance values of capacitive sensors, dedicated, among others, to capacitive relative humidity sensors. The method is based on a versatile direct sensor-to-microcontroller interface for microcontrollers with internal analog comparators (ACs) and with precision voltage reference sources, e.g. digital-to-analog converters (DACs). The reference...
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Experimental studies of circuit breaker drives and mechanisms diagnostics
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Gate Driver with Overcurrent Protection Circuit for GaN Transistors
PublikacjaThe improvement of the gate driver for GaN transistor is presented in this paper. The proposed topology contains the overcurrent protectionwith the two-stage turning off and independent control of turn on and off time of the GaN transistor. The operation of driver and its application in thehalf-bridge converter are described using both simulation and prototype measurements. The overcurrent protection was tested in Double Pulse...
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Transient States during Short-circuit in a Line Powered by UPS and its Impact on Earth Fault Loop Impedance Measurement and Power Quality
PublikacjaThe short-circuit in a line powered by Uninterruptible Power Supply (UPS) during different UPS operation modes is presented in the article. The transient state condition related to the short-circuit in a line fed from double conversion On-line UPS is discussed in detail. The results of the measurements of earth fault loop impedance (FLI) in circuits powered by UPS with the instruments of various manufacturers are presented. The...
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Practical aspects of testing superconducting electromagnets by the capacitor discharge method taking into account the non-linearity of circuit parameters
PublikacjaThe 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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A subdomain model for armature reaction field and open‐circuit field prediction in consequent pole permanent magnet machines
PublikacjaIn this paper, the machine quantity, such as electromagnetic torque, self and mutual inductances, and electromotive force, is analytically calculated for non-overlapping winding consequent pole slotted machine for open-circuit field and armature reaction. The sub-domain approach of (2-D) analytical model is developed using Maxwell's equations and divide the problem into slots, slot-openings, airgap and magnets region, the magnet...
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Anomalous diffusion modeling using ultracapacitors in domino ladder circuit
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Design and evaluation of a flow-to-frequency converter circuit with thermal feedback
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Predictive control of active filter system with LCL coupling circuit
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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
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Voltage dips reducyion with a hybrid contactless short circuit limiter.
PublikacjaW artykule przedstawiono działanie bezstykowego ogranicznika prądów zwarciowych w oparciu o symulację komputerową. Szczególną uwagę zwrócono na możliwość poprawy jakości dostarczanej energii, poprzez ograniczenia trwania zapadów napięcia w sieci elektroenergetycznej, dzięki zastosowaniu wyłącznika hybrydowego. Modelowanie matematyczne wykonano w programie MATLAB i PSPICE.
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New Methods of Short-Circuit Current Limiting and Switching-off
PublikacjaPrzedstawiono wyniki badań symulacyjnych i eksperymentalnych hybrydowych indukcyjno-tyrystorowych ograniczników i wyłączników prądu zwarciowego. Impedancja dławika ogranicznika prądu jest wtrącana do obwodu zwarciowego dopiero w chwili, gdy prąd zwarciowy przekroczy wartość prądu wymuszonego w dławiku przez zewnętrzne źródło prądu. Ograniczanie dynamiki prądu zwarciowego jest bezzwłoczne. Układ nie generuje przepięć łączeniowych....
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Hybrid inductance-thyristor short-circuit current limiting devices
PublikacjaDla wartości prądu w gałęzi w której zainstalowane jest urządzenie jest mniejsza od prądu w dławiku urządzenia, dławik jest zwarty gałęzią z tyrystorem. Impedancja bieguna urządzenia hybrydowego jest praktycznie równa zero. W chwili wzrostu prądu w gałęzi z urządzeniem ograniczającym ponad tę wartość, do obwodu głównego wtrącona zostaje impedancja kolejno dwóch dławików, ograniczając bezzwłocznie dynamikę i amplitudę prądu zwarciowego....
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Impulse Measurements of Tower Earthings of Overhead Transmission Lines
PublikacjaPrzepisy wymagają okresowego badania uziemień słupów elektroenergetycznych linii przesyłowych. pomiary takie metodami klasycznymi niskiej częstotliwości wymagają odłączania uziomów od konstrukcji słupa, co wiąże się z wyłączaniem linii. wykorzstanie metody udarowej do oceny uziemień nie wymaga odłączania uziomów i może byc przeprowadzane podczas pracy linii.
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Optimization-Based High-Frequency Circuit Miniaturization through Implicit and Explicit Constraint Handling: Recent Advances
PublikacjaMiniaturization trends in high-frequency electronics have led to accommodation challenges in the integration of the corresponding components. Size reduction thereof has become a practical necessity. At the same time, the increasing performance demands imposed on electronic systems remain in conflict with component miniaturization. On the practical side, the challenges related to handling design constraints are aggravated by the...
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Time-domain measurement methods for R, L and C sensors based on aversatile direct sensor-to-microcontroller interface circuit
PublikacjatIn the paper new time-domain measurement methods for determining values of resistive (R), inductive(L) and capacitive (C) sensors based on a versatile direct sensor-to-microcontroller interface for microcon-trollers with internal analog-to-digital converters (ADCs) and analog comparators (ACs) are presented.The interface circuit consists of a reference resistor Rrworking as a voltage divider, a given R, L or C sensorand a microcontroller...
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Noise modeling of static CMOS gates for low-noise circuit synthesis
PublikacjaW artykule przedstawiono efektywną metodę modelowania widma szumu napięcia zasilającego generowanego przez statyczne bramki cyfrowe CMOS. Metoda modelowania uwzględnia krótkie impulsy prądowe powstające w czasie przełączania bramek i pozwala oszacować górne limity widma szumu napięcia zasilającego co umożliwia niskoszumową syntezę układów cyfrowych.
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AC and DC global electric circuit and the height profile of atmospheric conductivity
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Slot harmonics in cage motors due to saturation of a main magnetic circuit
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A simplified behavioral MOSFET model based on parameters extraction for circuit simulations.
PublikacjaThe paper presents results on behavior modeling of general purpose Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) for simulation of power electronics systems requiring accuracy both in steady-state and in switching conditions. Methods of parameters extraction including nonlinearity of parasitic capacitances and steady-state characteristics are based on manufacturer data sheet and externally measurable characteristics....
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Iron Core Inductor High Frequency Circuit Model for EMC Application
PublikacjaW referacie przedstawiono szerokopasmowy model obwodowy dławika z rdzeniem ferromagnetycznym przydatny do analizy propagacji zaburzeń elektromagnetycznych przewodzonych w układach przekształtnikowych. Opracowany model uwzględnia zmiany właściowści dławika w zakresie wysokich cżstotliwosci na skutek występowania naskórkowości, prądów wirowych oraz efektu zbliżenia w uzwojeniach.
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Fractional Calculus Evaluation of Hyaluronic Acid Crosslinking in a Nanoscopic Part of Articular Cartilage Model System
PublikacjaThis work presents a study of the mechanism of physical crosslinking of hyaluronic acid in the presence of common phospholipids in synovial joint organ systems. Molecular dynamic simulations have been executed to understand the formation of hyaluronan networks at various phospholipid concentrations. The results of the simulations suggest that the mechanisms exhibit subdiffusion characteristics. Transportation quantities derive...
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High gain/bandwidth off‑chip antenna loaded with metamaterial unit‑cell impedance matching circuit for sub‑terahertz near‑field electronic systems
PublikacjaAn innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance...
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Simulation of Direct-Sequence Spread Spectrum Data Transmission System for Reliable Underwater Acoustic Communications
PublikacjaUnderwater acoustic communication (UAC) system designers tend to transmit as much information as possible, per unit of time, at as low as possible error rate. It is a particularly difficult task in a shallow underwater channel in which the signal suffers from strong time dispersion due to multipath propagation and refraction phenomena. The direct-sequence spread spectrum technique (DSSS) applied successfully in the latest standards...
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Brain circuit imprints of developmental 17α-Ethinylestradiol exposure in guppies (Poecilia reticulata): Persistent effects on anxiety but not on reproductive behaviour
PublikacjaThe effects of endocrine disruptors may vary with the timing of exposure. The physiological implications of adult exposure are present during and shortly after exposure while embryonic exposure can imprint changes manifested in adulthood. In this study, guppy (Poecilia reticulata) embryos were exposed to 2 and 20 ng/L of 17α-ethinylestradiol during development via the mother and reared in clean water from gestation until 6 months...
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Influence of the method of the control of the hybrid contactless short-circuit limiter on power quality
PublikacjaW artykule przedstawiono wpływ sterowania bezstykowego ogranicznika prądów zwarciowych na ograniczanie zapadów napięcia. Scharakteryzowano podstawowe własności ogranicznika oraz układu sterowania jego pracą. Ponieważ prąd zwarciowy jest detekowany przez dedykowany superkrótki bezpiecznik sterowanie musi być dostosowane do czasu przedrukowego i łukowego topika, które zależą od aktualnej wartości prądu i aktualnej konfiguracji obwodu....
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Influence of circuit breaker operation upon transformeros residual flux and inrush current
PublikacjaPrzedstawiono model i wyniki obliczeń prądu i strumienia magnetycznego w układzie zawierającym transformator trójfazowy i wyłącznik. Opracowano obwodowy model łącznika z łukiem elektrycznym. Model łuku zbudowano w oparciu o jego statyczną charakterystykę prądowo-napięciową z uwzględnieniem uproszczonej charakterystyki dynamicznej. Przeprowadzone symulacje wykazały, że wartość maksymalna prądu włączania transformatora zależy zarówno...
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Galvanic isolation circuit for measuring systems operating in environments with strong electromagnetic disturbances
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On the light intensity dependence of short-circuit current of bilayer organic photovoltaic cells
PublikacjaPraca przedstawia model zależności prądu zwarcia w organicznych dwuwarstwowych układach fotowoltaicznych od natężenia światła. Model jest oparty na założeniu jednorodnego pola elektrycznego w obu warstwach organicznych. Uwzględniona jest bimolekularna i monomolekularna rekombinacja nośników ładunku przy heterozłączu. Przedstawione zostało porównanie obliczeń teoretycznych i wyników doświadczalnych dla układów z barwnikiem perylenowym...
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Modeling saturation of main magnetic circuit of cage induction motors in presence of eccentricity
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Effects in stator currents of cage motors due to saturation of main magnetic circuit
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Interface circuit for impedance sensors using two specialized single-chip microsystems
PublikacjaW artykule przedstawiono obwód interfejsu przeznaczony do pomiaru parametrów impedancyjnych czujników lub celek pomiarowych instalowanych na obiektach technicznych. Umożliwia on pomiar modułu i argumentu impedancji w zakresie 10ohm
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Szczególny przypadek zastosowania obwodu elektrycznego. A particular case of electric circuit application
PublikacjaPrzedstawiono szczególne zastosowanie elektrycznego obwodu zastępczego dobadania hemodynamiki nerki. Cechą wyróżniającą taki obwód jest zasilanie napięciem pulsującym, którego kształt odpowiada zmianom ciśnienia tętniczego. Rozważono możliwość diagnostyki stanu nerki, czyli możliwość odtworzenia zmianami parametrów elektrycznych zmian patologicznych.
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Influence of ci rcuit parameters on the procces of current transfer in thehybrid circuit breaker.
PublikacjaW artykule przedstawiono działanie hybrydowego bezstykowego ogranicznika prądów zwarciowych w oparciu o symulację komputerową oraz porównanie eksperymentu z symulacją komputerową przy pomocy programu MATLAB i PSPICE. Przedstawiono również wady i zalety obliczeń numerycznych przeprowadzonych z zastosowaniem komercyjnych programów na analizę działania łącznika hybrydowego.W analizie uwzględniono model hybrydowego ogranicznika...
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Current commutation process in a ultra-fast fuse-IGBT hybrid circuit breaker.
PublikacjaUkład hybrydowy bezpiecznika topikowego i tranzystora IGBT umożliwia bardzo szybkie włączenie do obwodu zwarciowego impedancji ograniczającej wartość prądu. Po eksplozji krótkiego topika bezpiecznika wywołanej narastającym prądem zwarciowym wywołuje w czasie poniżej 2 ms wzrost napięcia na topiku do wartości ok.20 - 25V, po czym prąd jest komutowany do gałęzi z przyrządem półprzewodnikowym typu GTO lub IGBT. Ostateczne wyłączenie...
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Grand Challenges on the Theory of Modeling and Simulation
PublikacjaModeling & Simulation (M&S) is used in many different fields and has made many significant contributions. As a field in its own right, there have been many advances in methodologies and technologies. In 2002 a workshop was held in Dagstuhl, Germany, to reflect on the grand challenges facing M&S. Ten years on, a series of M& S Grand Challenge activities are marking a decade of progress and are providing an opportunity to reflect...
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Phosphorus removal by application of natural and semi-natural materials for possible recovery according to assumptions of circular economy and closed circuit of P
PublikacjaIn the last fewyears the idea of circular economy has become essential. Thus, designing methods of nutrients removal should be based on usingmaterials that make it possible to recover those nutrients. Recently,methods applied in wastewater treatment plants cannot provide optimal results; moreover, the application of commercial coagulants like ferric chloride and polyaluminumchloride can cause difficulties in potential recovery...
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Cross-talk modeling in coupled transmission lines terminated with nonlinear loads
PublikacjaW pracy przedstawiono przegląd dostępnych metod symulacji zjawiska przesłuchu kładąc szczegółny nacisk na efekty nieliniowości rzeczywistych obciążeń linii sygnałowych na płytach drukowanych. Wykorzystując metodę analizy opartą o szeregi Volterry przeanalizowano efekt przesłuchu w strukturze sprzężonych linii mikropaskowych obciążonych na wyjściu toru transmisyjnego diodą Schottky'ego z niską barierą potencjalu. Uzyskano bardzo...
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A compact microstrip rat-race coupler constituted by nonuniform transmission lines
PublikacjaIn this work, a step-by-step development of a compact microstrip rat-race coupler (RRC) has been presented and discussed. A high degree of miniaturization has been obtained by substituting six quarter-wavelength uniform atomic building blocks of a RRC by their nonuniform counterparts. The miniaturization procedure has been realized in three progressive steps: (i) the first layout solution of a miniaturized RRC has been acquired...