Filtry
wszystkich: 209
wybranych: 188
Wyniki wyszukiwania dla: topology
-
Reducing common mode voltage and bearing currents in quasi - resonant DC - link inverter
PublikacjaIn 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...
-
Integrated Three-Level Dual-Phase Inverter
PublikacjaIn view of reducing the number of inverter legs that provide dual-phase, three-level output voltages (as may be needed in an uninterruptible power supply), and that also provide a wide range of output frequencies (as needed in an advanced motor drive system with wide speed ranges), a three-level, dual-phase inverter topology is presented in this paper. Its three-level attribute was based on the F-type inverter topological concept,...
-
An application of multi-agent system for ship’s power systems design
PublikacjaDesign process of transport ship power system consists of structure (topology) and component elements selection. Compliance with the requirements for static components does not guarantee optimal dynamic characteristics of entire power system. Design steps are difficult to formalize and as a consequence to this reason expert and multi-agent systems are used for solving selected design issues. In the paper distributed multi-agent...
-
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...
-
Network Graph Transformation Providing Fast Calculation of Paths for Resilient Routing
PublikacjaProtection of transmission against failures can be appropriately dealt with by alternative paths. However, common schemes (e.g., Bhandaris scheme) are characterized by a remarkable delay while determining the transmission paths. This in turn may have a serious impact on serving dynamic demands (characterized by relatively short duration time). As a remedy to this problem, we introduce an approach to pre-compute the sets of disjoint...
-
Optimal Multivariable Control for Modified Z-source Based IPT
PublikacjaThis 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...
-
Voltage Source Power Line Conditioner for Applications in Local Supply Systems
PublikacjaThe paper presents the basic principles of operation of voltage source power line conditioners (VSPLC) as well as their energy and filtration properties. A 4-level cascade based Voltage Source Converter (VSC) is used as a voltage source. The advantages of this topology is relatively simple construction and simple way of balancing DC link voltages. Results of the theoretical and experimental investigations confirm good energetic...
-
A novel approach to energy safety improvement in the marine power plants with active power surge compensator
PublikacjaPaper raises a point of power surges and theirs adverse effects in the marine power plants. The article explains a source of surges appearance, and presents measurements carried out on a modern ship. It discusses effects of dynamic power transients on the ship’s energy safety. Finally it proposes, a novel approach for power surge elimination, based on medium voltage active conditioner. As well as it propose the topology and control...
-
Jednofazowy falownik napięcia z aktywnym obwodem odsprzęgającym
PublikacjaZnanym zagadnieniem w jednofazowych falownikach napięcia jest pobieranie ze źródła napięcia stałego składowej przemiennej o częstotliwości dwukrotnie większej od częstotliwości generowanej przez falownik. Jednym z rozwiązań problemu jest stosowanie dużej baterii kondensatorów elektrolitycznych, lecz lepszym sposobem z punktu widzenia niezawodności i gęstości mocy przekształtnika jest stosowanie aktywnych układów odsprzęgania mocy....
-
Toward Fast Calculation of Communication Paths for Resilient Routing
PublikacjaUtilization of alternate communication paths is a common technique to provide protection of transmission against failures of network nodes/links. However, a noticeable delay is encountered when calculating the relevant sets of disjoint paths using the available algorithms (e.g., using Bhandari’s approach). This, in turn, may have a serious impact on the ability of a network to serve dynamic demands...
-
Client-side versus server-side geographic data processing performance comparison: Data and code
PublikacjaThe data and code presented in this article are related to the research article entitled “Analysis of Server-side and Client-side Web-GIS data processing methods on the example of JTS and JSTS using open data from OSM and Geoportal” (Kulawiak et al., 2019). The provided 12 datasets include multi-point and multi-polygon data of different scales and volumes, representing real-world geographic features. The datasets cover the area...
-
Lead(II) coordination polymers with imidazole-4- and pyrazole-3-carboxylate isomeric linkers: Structural diversity and luminescence properties
PublikacjaUsing 1H-imidazole-4-carboxylic acid (4imCOOH) and 1H-pyrazole-3-carboxylic acid (3pyrCOOH) coordination polymers [Pb(4imCOO)2(H2O)]n (1) and [Pb2(3pyrCOO)4]n (2) were constructed. Obtained polymers were characterized via FT-IR, X-ray, PL and TG methods. The coordination polyhedron around Pb(II) in 1 is described as distorted pentagonal pyramid with hemidirected coordination sphere (based on DFT calculations). Compound 2 consists...
-
New type T-Source inverter
PublikacjaThis paper presents different topologies of voltage inverters with alternative input LC networks. The basic topology is known in the literature as a Z-source inverter (ZSI). Alternative passive networks were named by the authors as T-sources. T-source inverter has fewer reactive components in comparison to conventional Z-source inverter. The most significant advantage of the T-source inverter (TSI) is its use of a common voltage...
-
Four Level Diode-Clamped Back-To-Back Converter with Active DC Link Voltage Control
PublikacjaThis 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...
-
An unusual four-nuclear Pb(II)-pyrrole-2-carboxylato polymer: The effect of the lone pair and non-covalent interactions on the supramolecular assembly and fluorescence properties
PublikacjaThe reaction of Pb(NO3)2 with 1H-pyrrole-2-carboxylic acid (2prCOOH) leads to the formation of a new four-nuclear Pb(II) polymer, [Pb4(2prCOO)8(H2O)]n, which has been characterized by CHN, FT-IR, TG, PL and single-crystal X-ray diffraction methods. In view of the primary Pb–O bonds, Pb1 and Pb3 show hemidirected pentagonal pyramidal geometries, while Pb2 and Pb4 display hemidirected octahedral geometries. The topology of the strongest...
-
Expedited antenna optimization with numerical derivatives and gradient change tracking
PublikacjaDesign automation has been playing an increasing role in the development of novel antenna structures for various applications. One of its aspects is electromagnetic (EM)-driven design closure, typically applied upon establishing the antenna topology, and aiming at adjustment of geometry parameters to boost the performance figures as much as possible. Parametric optimization is often realized using local methods given usually reasonable...
-
Koncepcja i symulacja polowa generatora o zmiennej częstotliwości. Zastosowanie w autonomicznych systemach elektroenergetycznych = Conception and field simulations of a variable frequency generator. Application for autonomous power generation system
PublikacjaStreszczenie angielskie: This paper covers a conception and simulation results for a brushless synchronous generator working with variable speed in an autonomous energy generation system (e.g. airplane power grid, hybrid vehicle, micro-CHP). The papers has two parts: presentation of the generator conception used in modern autonomous energy generation systems, and simulation results using filed model elaborated in Flux2D software....
-
Generalized Dold sequences on partially-ordered sets
PublikacjaDold sequences constitute an important class of integer sequences that play an important role in combinatorics, number theory, topology and dynamical systems. We generalize the notion of Dold sequence for the case of partially ordered sets and describe their properties. In particular we give two alternative descriptions of generalized Dold sequences: by some class of elementary sequences as well as by different...
-
Effect of mesh deformation on the accuracy of 3D FEM electromagnetic analysis
PublikacjaIn this paper, the accuracy of 3D FEM electromagnetic simulations in parametric analysis using mesh deformation techniques is discussed. Mesh deformation techniques allow one to preserve the mesh topology while the geometry is changed. It is shown that the application of mesh deformation can provide accurate simulation results even for very large deformations. On the other hand, it is also shown that the technique has to be used...
-
Selfish Attacks in Two-Hop IEEE 802.11 Relay Networks: Impact and Countermeasures
PublikacjaIn IEEE 802.11 networks, selfish stations can pursue a better quality of service through selfish MAC-layer attacks. Such attacks are easy to perform, secure routing protocols do not prevent them, and their detection may be complex. Two-hop relay topologies allow a new angle of attack: a selfish relay can tamper with either source traffic, transit traffic, or both. We consider the applicability of selfish attacks and their variants...
-
Nowoczesne układy przekształtników wielopoziomowych do zasilania statków z lądu
PublikacjaW artykule poruszono tematykę zasilania statków zacumowanych w porcie z lądowej sieci elektroenergetycznej poprzez wykorzystanie nowoczesnych konstrukcji przekształtników energoelektronicznych. W treści pracy zaprezentowano porównanie dwóch topologii wysokonapięciowych przekształtników wielopoziomowych. Porównano konstrukcje przekształtników z klasycznym transformatorem wielouzwojeniowym oraz z transformatorami wysokoczęstotliwościowymi.
-
Przegląd systemów ładowania elektrycznych osobowych pojazdów i koncepcja dwukierunkowej ładowarki pokładowej
PublikacjaAktualnie trwa intensywny rozwój pojazdów elektrycznych (EV) i hybrydowych typu plug-in (PHEV) z pokładowymi bateriami akumulatorów. Badania w tej dziedzinie skupiają się na maksymalizowaniu sprawności oraz minimalizowaniu masy i objętości systemów ładowania baterii. W artykule przedstawiono podział systemów ładowania osobowych pojazdów typu EV/PHEV. Opisano systemy ładowania przewodowego z podziałem na ładowarki pokładowe i zewnętrzne, systemy...
-
Thermodynamic, Anticoagulant, and Antiproliferative Properties of Thrombin Binding Aptamer Containing Novel UNA Derivative
PublikacjaThrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain...
-
Mechanical Properties, Microstructure and Surface Quality of Polypropylene Green Composites as a Function of Sunflower Husk Waste Filler Particle Size and Content
PublikacjaAgricultural waste is a still untapped source of materials that can, in case of proper utilization, significantly improve the sustainability of polymers and their composites. In this work, polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt% and 20 wt%. The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects...
-
Highly-Miniaturized Dual-Mode Bandpass Filter Based on Quarter-Mode Substrate Integrated Waveguide with Wide Stopband
PublikacjaThis paper presents a novel design of a highly-miniaturized dual-mode bandpass filter (BPF) employing a quarter-mode substrate integrated waveguide (QMSIW). The QMSIW resonator is based on a square cavity with metallic vias along two sides, and open-ended edges at the remaining sides that contain orthogonal feed lines. An open slot is introduced along the two sides of the square cavity with metallic vias to form a magnetic wall....
-
Novel Versatile Topologies and Design Optimization of Wide-Bandstop Frequency Selective Surfaces for X-Band, Ku-Band and Millimeter-Wave Applications
PublikacjaNovel designs of frequency selective surface (FSS) are presented for wideband applications in X, Ku and mmWave (millimeter Wave) bands. Two identical metallic layers of FSS are imprinted on both sides of the RO4003 substrate. The geometry parameters are optimized to maximize the bandstop at the specified in-band maximum transmission level of –10 dB; satisfaction of the latter condition is enforced through appropriate formulation...
-
Hybrid piezoelectric motor based on electroactive lubrication principle
PublikacjaA novel conception of hybrid piezoelectric motor is presented in this paper. Proposed conception required synchronised work of quasi-static and resonant piezoelectric actuators that results in a rotary movement. The motor's working principle is explained and the main characteristics are described. Studied topology is compared to the existing piezoelectric motors with regards to its field of applications. The assembling process...
-
Design of battery charging system update for glider launcher
PublikacjaThis paper presents an innovative solution for increasing life of lead-acid batteries used in a glider launcher. The study is focused on upgrading a charging system instead of a costly full replacement of it. Based on literature review, the advanced three-stage charging profile was indicated. The new topology of the power converter was proposed and a simulation model was developed. A simulation study was performed which leads to...
-
Local Mesh Deformation for accelerated parametric studies based on the Finite Element Method
PublikacjaThis paper presents an approach for enhancing the efficiency of two-dimensional Finite Element Method analysis in parametric studies or optimisation process of microwave components. The new approach involves local mesh deformation applied near the elements that are modified during computations. Since in the proposed approach the topology of the mesh remains unchanged, a new mesh does not have to be generated from scratch when the...
-
The impact of the overhead line's power supply system spatial differentiation on the energy consumption of trolleybus transport: planning and economic aspects
PublikacjaNowadays the issue of electric energy saving in public transport is becoming a key area of interest, which is connected both with a growth in environmental awareness of the society and an increase in the prices of fuel and electricity. It can be achieved by reducing of the transmission losses in supply system or by the improving of the usage of the regenerative breaking. The spatial differentiation of the energy supply system of...
-
Deterministic Rendezvous in Restricted Graphs
PublikacjaIn this paper we consider the problem of synchronous rendezvous in which two anonymous mobile entities (robots) A and B are expected to meet at the same time and point in a graph G = (V;E). Most of the work devoted to rendezvous in graphs assumes that robots have access to the same sets of nodes and edges, where the topology of connections may be initially known or unknown. In our work we assume the movement of robots is restricted...
-
Przekształtniki tranzystorowe działające w trybie prądu trójkątnego
PublikacjaPrzekształtniki oparte na węgliku krzemu mogą być analizowane jako źródła napięcia lub prądu niezależnie od topologii przy odpowiednich parametrach filtru wyjściowego. Szczególnie interesujące są falowniki napięcia działające w trybie prądu trójkątnego. W referacie przedstawiono sterowanie trójfazowym falownikiem napięcia posiadającym właściwości źródła prądu. Pokazano, jak dobrać parametry filtru wyjściowego falownika. Oceniono...
-
A Trisection Filter Design With Negative Slope of Frequency-Dependent Crosscoupling Implemented in Substrate Integrated Waveguide (SIW)
PublikacjaThis letter reports on a novel realization of a microwave bandpass filter in a triplet configuration with a frequency-dependent crosscoupling implemented in substrate integrated waveguide (SIW). The design involves implementing dispersive coupling with a negative slope, a feature that allows the capabilities of the classic triplet topology to be extended. In this particular case, the implementation of two transmission zeros on...
-
Quasi-resonant DC-link voltage inverter with enhanced zero-voltage switching control
PublikacjaA 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...
-
Koncepcja i analiza sensora/aktuatora piezoelektrycznego do pomiaru procesu starzenia się ludzkiej skóry
PublikacjaNiniejszy artykuł przedstawia nową koncepcję piezoelektrycznego sensora/aktuatora przeznaczonego do pomiaru właściwości mechanicznych tkanek miękkich a w szczególności skóry ludzkiej. Wyjaśnione jest analityczne podejście z wykorzystaniem schematu zastępczego Mason’a określającego aktuator w stanie rezonansu oraz opis metody impedancji elektromechanicznej wykorzystanej w systemie pomiarowym. Analiza z użyciem metody elementów...
-
Exploring thiophene-2-acetate and thiophene-3-acetate binding modes towards the molecular and supramolecular structures and photoluminescence properties of Pb(ii) polymers
PublikacjaTo evaluate the impact of the flexible positional isomeric ligands thiophene-2-acetate (2tpacCOO) andthiophene-3-acetate (3tpacCOO) on the construction and self-assembly process of Pb(II) polymers, twonovel compounds, [Pb(2tpacCOO)2(H2O)]n(1) and [Pb(3tpacCOO)2]n(2), were preparedviaanonhydro-thermal method with respect to green chemistry rules. The obtained polymers were fully characterized byelemental analysis, TG/DTG and PXRD,...
-
On Unsupervised Artificial-Intelligence-Assisted Design of Antennas for High-Performance Planar Devices
PublikacjaDesign of modern antenna structures is a challenging endeavor. It is laborious, and heavily reliant on engineering insight and experience, especially at the initial stages oriented towards the devel-opment of a suitable antenna architecture. Due to its interactive nature and hands-on procedures (mainly parametric studies) for validating suitability of particular geometric setups, typical antenna development requires many weeks...
-
On the Existence of Homoclinic Type Solutions of a Class of Inhomogenous Second Order Hamiltonian Systems
PublikacjaWe show the existence of homoclinic type solutions of a class of inhomogenous second order Hamiltonian systems, where a C1-smooth potential satisfies a relaxed superquadratic growth condition, its gradient is bounded in the time variable, and a forcing term is sufficiently small in the space of square integrable functions. The idea of our proof is to approximate the original system by time-periodic ones, with larger and larger...
-
Polyarmonic model of synchronous generator for analysis of autonomous power generation systems
PublikacjaAbstract: This paper presents the polyharmonic modelling of synchronous generator (SG) in machine variables. The simple geometry and windings physical layout has been used for inductance calculations of a salient-pole SG. The main advantage of this model is the ease of describing an autonomous power generation system (APGS) in terms of its topology and thus providing effective analysis at the static and dynamic states, both for...
-
Performance of LSP preemption methods in different MPLS networks
PublikacjaPreemption in Multiprotocol Label Switching (MPLS) is an optional traffic engineering technique used to create a new path of high priority when there is not enough bandwidth available. In such case the path is admitted by removing one or more previously allocated paths of lower priority. As there are usually many possible sets of low priority paths which can be selected, a preemption algorithm is being started to select the best...
-
Approximative sequences and almost homoclinic solutions for a class of second order perturbed Hamiltonian systems
PublikacjaIn this work we will consider a class of second order perturbed Hamiltonian systems with a superquadratic growth condition on a time periodic potential and a small aperiodic forcing term. To get an almost homoclinic solution we approximate the original system by time periodic ones with larger and larger time periods. These approximative systems admit periodic solutions, and an almost homoclinic solution for the original system...
-
INFLUENCE OF A VERTEX REMOVING ON THE CONNECTED DOMINATION NUMBER – APPLICATION TO AD-HOC WIRELESS NETWORKS
PublikacjaA minimum connected dominating set (MCDS) can be used as virtual backbone in ad-hoc wireless networks for efficient routing and broadcasting tasks. To find the MCDS is an NP- complete problem even in unit disk graphs. Many suboptimal algorithms are reported in the literature to find the MCDS using local information instead to use global network knowledge, achieving an important reduction in complexity. Since a wireless network...
-
Geospatial Coverage and Signal Quality Measurements of Terrestrial DAB+ Network in Northern Poland
PublikacjaModern signal coverage maps are prepared based on industry-standard radio propagation models, which take into account a number of parameters, including: type of antenna, distance from the transmitter, type of terrain, etc. However, such simulations are prone to location-specific inaccuracies, and should be verified with in-situ measurements. This paper presents results of a field test of a terrestrial DAB+ (Digital Audio Broadcasting...
-
Practical Approach to IP Scheduled Throughput Measurements in Dual Connectivity Systems
PublikacjaIP scheduled throughput defined according to 3GPP TS 36.314 reflects user throughput regardless of traffic characteristics, and therefore has become one of the most important indicators for monitoring Quality of Service (QoS) of the end user in Evolved Universal Terrestrial Radio Access Network (E-UTRAN). However, networks built on a distributed architecture make the above definition impossible to be applied directly due to the...
-
Unity-Gain Zero-Offset CMOS Buffer with Improved Feedforward Path
PublikacjaA voltage unity-gain zero-offset CMOS amplifier with reduced gain error and increased PSRR (power supply rejection ratio) is proposed. The amplifier uses two feed mechanisms, negative feedback and supporting positive feedforward, to achieve low deviation from unit gain over the entire input range. The circuit, designed in a standard 180-nanometer 1.8-voltage CMOS process, is compared with two known buffers of similar topology,...
-
Design and Optimization of a Compact Planar Radiator for UWB Applications and Beyond
PublikacjaA compact monopole antenna for ultra-wideband (UWB) and beyond applications has been proposed. The radiator is based on the monopole topology. The super-wideband behavior has been achieved using a combination of spline-based modifications applied to the driven element, as well as utilization of a tapered feed and a slot-modified ground plane. The electrical performance of the structure has been tuned using a numerical optimization...
-
Constructive Controllability for Incompressible Vector Fields
PublikacjaWe give a constructive proof of a global controllability result for an autonomous system of ODEs guided by bounded locally Lipschitz and divergence free (i.e. incompressible) vector field, when the phase space is the whole Euclidean space and the vector field satisfies so-called vanishing mean drift condition. For the case when the ODE is defined over some smooth compact connected Riemannian manifold, we significantly strengthen...
-
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...
-
Model of control plane of ASON/GMPLS network
PublikacjaASON (Automatic Switched Optical Network) is a concept of optical network recommended in G.8080/Y.1304 by ITU-T. Control Plane of this network could be based on GMPLS (Generalized Multi-Protocol Label Switching) protocols. This solution, an ASON control plane built on GMPLS protocols is named ASON/GMPLS. In the paper, we decompose the control plane problem and show the main concepts of ASON network. We propose a hierarchical architecture...
-
Energy recovery effectiveness in trolleybus transport
PublikacjaNowadays the issue of electric energy saving in public transport is becoming a key area of interest whichis connected both with a growth in environmental awareness of the society and an increase in the pricesof fuel and electricity. One of the possibilities to reduce energy consumption in urban public transport isto increase the extent of regenerative braking energy utilization. This can be achieved by its accumulationin the supercapacitors...