Search results for: EARTH FAULT CURRENTS
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Double Fed Induction Machine Drives
PublicationContents of the Chapter 22:Machine model.Properties of the DFM.Steady state machine operation.Control rules and decoupled control.Decoupling based on MM machine model.Decoupling based on vector model.Decoupling based on rotor current equation.Overall control system.Control system based on MM model.Control system based on vector model.Estimation of variables.Calculation of the angle between stator and rotor.Remarks about digital...
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Thermal behaviour of NH4VO3 microcasketoids
Open Research DataThe DataSet contains the results of the thermal behavior of the ammonium metavanadate microcasketoids under argon and nitrogen atmosphere. Thermogravimetric analysis (TG) was carried out under argon or nitrogen atmosphere from 40C to 560C (with a heating rate of 10 C/min) using Netzsch STA 449 F1. The thermal behavior was also studied with mass spectrum...
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Thermal behaviour of NH4VO3 nanoflowers
Open Research DataThe DataSet contains the results of the thermal behavior of the ammonium metavanadate nanoflowers under argon and nitrogen atmosphere. Thermogravimetric analysis (TG) was carried out under argon or nitrogen atmosphere from 40C to 560C (with a heating rate of 10 C/min) using Netzsch STA 449 F1. The thermal behavior was also studied with mass spectrum...
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Thermal behaviour of NH4VO3 elongated microcrystals
Open Research DataThe DataSet contains the results of the thermal behavior of the ammonium metavanadate elongated microcrystals under argon and nitrogen atmosphere. Thermogravimetric analysis (TG) was carried out under argon or nitrogen atmosphere from 40C to 560C (with a heating rate of 10 C/min) using Netzsch STA 449 F1. The thermal behavior was also studied with mass...
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Thermal behaviour of NH4VO3 microflowers
Open Research DataThe DataSet contains the results of the thermal behavior of the ammonium metavanadate microflowers under argon and nitrogen atmosphere. Thermogravimetric analysis (TG) was carried out under argon or nitrogen atmosphere from 40C to 560C (with a heating rate of 10 C/min) using Netzsch STA 449 F1. The thermal behavior was also studied with mass spectrum...
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Thermal behaviour of ammonium vanadate nanocrystals
Open Research DataThe DataSet contains the thermal behavior of the ammonium vanadate nanostructures obtained by the hydrothermal method with different conditions. Thermogravimetric analysis (TG) was carried out under an argon atmosphere from 40C to 560C (with a heating rate of 10 C/min) using Netzsch STA 449 F1. The thermal behavior was also studied with mass spectrum...
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Thermal behaviour of commercial avaible NH4VO3
Open Research DataThe DataSet contains the results of the thermal behavior of the commercially available ammonium metavanadate (CAS 7803-55-6) under argon and nitrogen atmosphere. Thermogravimetric analysis (TG) was carried out under argon or nitrogen atmosphere from 40C to 560C (with a heating rate of 10 C/min) using Netzsch STA 449 F1. The thermal behavior was also...
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Elemental composition, environment of deposition of the Lower Carboniferous Emma Fiord Formation oil shale in Arctic Canada
PublicationThe sedimentary succession of 51-m consisting of a thin coal seam (1 m) and oil shale with a marlstone and carbonate-mudstone matrix of the Lower Carboniferous (Viséan) Emma Fiord Formation located on the Grinnell Peninsula, Devon Island, Arctic Canada was examined. The techniques used include reflected light microscopy, and instrumental neutron activation analysis (INAA) for elemental concentration, and inductively coupled plasma...
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Problem of Clogging in Drainage Systems in the Examples of the Zur and Podgaje Dams
PublicationDrainage plays an extremely important role in hydraulic structures, such as earth dams. Observations of drainage in hydraulic structures under various soil conditions indicate that the phenomenon of clogging can lead to a radical reduction in the efficiency of drainage, making it non-functional within a few years after construction. This article describes the problems of drainage clogging by iron oxide in the examples of the Zur...
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Reduction of the Velocity Impact on the Magnetic Flux Leakage Signal
PublicationThe velocity effect on the magnetic flux leakage (MFL) signal was investigated in this paper. Experiments were performed for velocity of the MFL tool within the range of 0–2 m/s. The velocity was not constant during each measurement to imitate real operational conditions of the MFL tool. Two components of the leakage were measured, i.e. the tangential to the motion direction (x) and the normal to the investigated surface (z). In...
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Analiza przepływu gazu w kanałowych reduktorach ciśnienia podczas zwarć łukowych w rozdzielnicach SN
PublicationW artykule przedstawiono metodę obliczania ciśnienia i temperatury gazów podczas zwarcia łukowego wewnątrz przedziału wyłącznika rozdzielnicy średniego napięcia z wykorzystaniem modelu termodynamicznego procesów towarzyszących zwarciom łukowym wewnątrz rozdzielnic z izolacją powietrzną. Następnie, w oparciu o mechanikę płynów lepkich, przedstawiono metodę obliczania rozkładu prędkości i ciśnienia gazu w kanałowych reduktorach ciśnienia...
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General Provisioning Strategy for Local Specialized Cloud Computing Environments
PublicationThe well-known management strategies in cloud computing based on SLA requirements are considered. A deterministic parallel provisioning algorithm has been prepared and used to show its behavior for three different requirements: load balancing, consolidation, and fault tolerance. The impact of these strategies on the total execution time of different sets of services is analyzed for randomly chosen sets of data. This makes it possible...
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Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces
PublicationThis article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under...
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AC motor feeding cable consequences on EMC performance of ASD
PublicationHigh level of conducted EMI emissions of adjustable speed drives (ASD) is one of the most difficult problems in contemporary applications. Many investigations are carried out in order to find more effective methods allowing to predict this emission at early stage of design, and therefore to predict adequate countermeasures. This paper deals with the method which allows to estimate by simulation the influence of motor feeding cable...
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Arctic as a reservoir for polycyclic aromatic hydrocarbons and polychlorinated biphenyls- water samples from Foxfonna glacier
PublicationPolycyclic aromatic hydrocarbons and polychlorinated biphenyls are groups of stable compounds, hard to biodegrade, potentially toxic. Their presence in Arctic environment may have a big impact on natural balance, fauna and flora. Although Arctic areas should be unpolluted, some amounts of pollutants are transferred from lower latitudes with sea currents and air masses. This paper presents the amounts of selected persistent organic...
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Magnetic signature reproduction of ferromagnetic ships at arbitrary geographical position, direction and depth using a multi-dipole model – source and verification dataset with description
Open Research DataThe dataset include source synthetic magnetic data concerning the corvette-type ship numeric model. The data are for 6 locations around the World with different V1 ÷ V6 Earth magnetic field values. The attached data is in Matlab. MAT format, but the data can also be used in Octave software.
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Au-RE-TiO2 nanocomposites: Surface characteristics and photoactivity
PublicationThe photocatalysts based on TiO2 co-doped with rare earth metal (RE) and gold nanoparticles have been prepared using a sol-gel method and followed by gold reduction. Specific surface areas of the modified photocatalysts were calculated by the Brunauer-Emmett-Teller method (BET). Diffuse reflectance spectra of the obtained photocatalysts were recorded in a UV-Vis spectrophotometer (DRS UV-Vis). The influence of the type of rare...
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ANALIZA WPŁYWU NIEJEDNOCZESNOŚCI ZAMYKANIA BIEGUNÓW ŁĄCZNIKA NA PRĄDY ZAŁĄCZENIOWE TRANSFORMATORA W STANIE JAŁOWYM
PublicationW artykule przedstawiono wyniki obliczeń symulacyjnych prądów załączeniowych transformatora dla różnych sekwencji zamykania biegunów łącznika. Sekwencje różniły się kolejnością łączenia faz oraz czasami opóźnienia w zamykaniu biegunów. Rozważono także kilka wariantów stanu namagnesowania szczątkowego rdzenia. Na podstawie analizy wyników stwierdzono, że przy jednoczesnym zamykaniu biegunów łącznika, właściwy dobór chwili załączenia...
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Hydrometeorological and hydrochemical conditions in the Gulf of Gdańsk in the vicinity of Vistula river mouth in July of 1977
Open Research DataSome results of the complex measurements in the coastal zone of the Gulf of Gdańsk in the vicinity of the Vistula river mouth are included in this archival data set. The measurements were carried out by Institute of the Oceanography of the University of Gdańsk (IO UG) in July of 1977. The list of parameters includes wind direction and speed, Secchi...
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O projektowaniu ściany szczelinowej
PublicationW pracy przedstawiono proces weryfikacji i porównania obliczeń otrzymanych z programu bazującego na metodzie elementów skończonych z wynikami analitycznymi dla analizowanej ściany szczelinowej z przyporą ziemną. Dodatkowo autorzy dokonali krótkiego przeglądu literatury z zakresu ścian szczelinowych.
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Luminescence properties of TeOx-2%Eu1.5%Tb1.5%Dy thin films annealing under an oxidizing atmosphere
Open Research DataThe DataSet contains the emission and excitation spectra of TeOx-2%Eu1.5%Tb1.5%Dy thin films. The material was obtained by the sol-gel method. The starting solution was prepared by mixing telluric acid (precursor) with thetraetylene glycol, water, and ethanol. Next, the 5% mol of rare-earth ions were added, the nitrates were used as a source of rare-earth...
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Luminescence properties of TeOx-2%Eu1.5%Tb1.5%Tm thin films annealing under an oxidizing atmosphere
Open Research DataThe DataSet contains the emission and excitation spectra of TeOx-2%Eu1.5%Tb1.5%Tm thin films. The material was obtained by the sol-gel method. The starting solution was prepared by mixing telluric acid (precursor) with thetraetylene glycol, water, and ethanol. Next, the 5% mol of rare-earth ions were added, the nitrates were used as a source of rare-earth...
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Luminescence properties of TeOx-1%Eu1.5%Tb2.5%Dy thin films annealing under an oxidizing atmosphere
Open Research DataThe DataSet contains the emission and excitation spectra of TeOx-1%Eu1.5%Tb2.5%Dy thin films. The material was obtained by the sol-gel method. The starting solution was prepared by mixing telluric acid (precursor) with thetraetylene glycol, water, and ethanol. Next, the 5% mol of rare-earth ions were added, the nitrates were used as a source of rare-earth...
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Impulse Impedance Measurements of Lightning Protection Earthings
PublicationLightning protection earthing systems should be tested at currents with time parameters similar to those of lightnings. A method and definition of a measured value of impulse impedance are introduced. The impulse impedance was determined by a quotient of voltage drop on the tested earthing to a value of current in measure circuit. The usefulness of the impulse method for lightning protection evaluation is tested on radio base stations...
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Analysis of degaussing process of ferromagnetic objects
PublicationResults of the analytical and numerical analysis of the degaussing process phenomena of ferromagnetic objects were presented in this paper. The screening effectiveness of the electromagnetic field of magnetic screens in most cases depends on thickness, conductivity, magnetic permeability of the screen and angular frequency of degaussing currents. The magnetic field inside thin-layer ferromagnetic object was presented in this paper....
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Bogdan Wiszniewski prof. dr hab. inż.
PeopleBogdan Wiszniewski graduated from Gdansk University of Technology in 1977 and was awarded an MSc in computer science and engineering with honours. In 1984 and 1998, respectively, has got his PhD and DSc. In 2006 was awarded a Professor title by the President of Poland. Lectured at the universities in Canada, US and UK. Principal investigator or coordinator in many national and international R&D projects with the significant...
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Absence of superconductivity in fluorine-doped neptunium pnictide NpFeAsO
PublicationX-ray diffraction, specific heat, magnetic susceptibility and inelastic x-ray scattering measurements on the transurarium oxypnictides NpFeAsO and NpFeAsO0.85F0.15 are presented. No superconductivity down to 2 K was observed upon fluorine doping, contrary to the structurally analogous rare-earth pnictides. No modification of the phonon density of states was observed upon doping with fluorine. We discuss our results in light of...
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Zbigniew Łubniewski dr hab. inż.
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Compensation of Dead Time Effects for Shunt Active Power Filters
PublicationThe paper presents a comprehensive approach to the compensation of the grid current distortion for shunt active power filter systems. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the estimation of compensating currents and grid voltages, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Diagnostics of zno varistors by means of nondestructive testing
PublicationStandard industrial testing of high-voltage varistors for surge arresters demands application of high voltages and intensive currents. Nondestructive methods for varistor quality and endurance evaluation have been proposed and described. They rely on the application of resonant ultrasound spectroscopy, electro-ultrasonic spectroscopy, noise measurement and nonlinearity testing at voltages lower than continuous operating range....
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Internet photogrammetry as a tool for e-learning
PublicationAlong with Internet development, there were interactive applications which allow for remote sensing and photogrammetric analysis. An example of an application that can provide Earth images and make it possible to measure distances in these images is Google Earth. The authors, who have experience from 2001-2015 argue that it is possible and it is important to create more advanced photogrammetric network applications. In this there...
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Machine learning-based prediction of seismic limit-state capacity of steel moment-resisting frames considering soil-structure interaction
PublicationRegarding the unpredictable and complex nature of seismic excitations, there is a need for vulnerability assessment of newly constructed or existing structures. Predicting the seismic limit-state capacity of steel Moment-Resisting Frames (MRFs) can help designers to have a preliminary estimation and improve their views about the seismic performance of the designed structure. This study improved data-driven decision techniques in...
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Early Oceanographical Data Collected by the Institute of Oceanography, University of Gdańsk
PublicationThree data sets entitled Water currents in Głębinka Passage in late spring of 1975, Hydrometeorological and hydrochemical conditions in the Gulf of Gdańsk in the vicinity of Vistula river mouth in July of 1977, and Gulf of Gdańsk monitoring conducted by the Institute of Oceanography, University of Gdańsk, in 1981–1994 contain archival field measurement results from the Gulf of Gdańsk (the southern Baltic). The data can be used...
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Compensation of supply current harmonics, reactive power, and unbalanced load current balance in the closed-loop control of a shunt active power filter
PublicationThis paper presents the compensation tasks performed by a shunt active power filter, including compensation of harmonic currents, reactive power, and an unbalanced load current. The paper demonstrates novel control of the shunt active power filter in a closed-loop system. The control algorithm was verified by performing simulations and compared the simulated results with those obtained in an open-loop control system. All simulations...
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Routing decisions independent of queuing delays in broadband leo networks
PublicationThis paper presents an analysis of queuing and propagation delays of Inter-Satellite Links (ISLs) in broadband Low-Earth Orbit (LEO) satellite networks. It is shown that queuing delays are negligible in all reasonable working conditions of the broadband ISL network. This fact makes it possible to simplify the routing protocols in such networks and permits using already known multi-commodity flow solutions for routing. The performance...
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Performance analysis of power swing blocking feature in ABB 670 series impedance relays
PublicationThis paper presents test results of a distance protection’s PSD power swing detection feature in ABB 670 series relays. A RED670 relay was tested, which is part of the hydroelectric set protection in Żarnowiec Pumped Storage Plant. The power swing blocking feature’s performance was analysed on the basis of the results of object tests made with an Omicron digital tester. Also presented are simulation results that illustrate the...
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SELECTION OF DIAGNOSTIC FUNCTIONS IN A WHEELED TRACTOR
PublicationIn a classical approach to damage diagnosis, the technical condition of an analyzed machine is identified based on the measured symptoms, such as performance, thermal state or vibration parameters. In wheeled tractor the fundamental importance has monitoring and diagnostics during exploitation concerning technical inspection and fault element localizations. The main functions of a diagnostic system are: monitoring tractor components...
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Sol-gel derived TeO2:RE powders
Open Research DataTellurium dioxide powders doped by Europium or Dysprosium were prepared by sol-gel method. Samples were annealed in ix of Ar and O2 atomosphere at 600 degrees. Presence of rare earth dopants and Te4+ phase was confirmed by X-Ray Photoemission Spectroscopy method (XPS). For XPS measurements samples with 1 atomic % and 5 atomic % of dopand were selected.
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A predictive estimation based control strategy for a quasi-resonant dc-link inverter
PublicationIn this paper the predictive estimation based control strategy for a quasi-resonant dc link inverter (PQRDCLI) is developed. Instead of direct measurement of dc link input inverter current – its estimation with one step prediction is applied. The PQRDCLI fed induction motor, controlled with a predictive current estimation stabilized inverter output voltage slopes independently of load. Moreover, reduction of overvoltage spikes...
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Detection and time/frequency analysis of electric fields in the ground
PublicationThis paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis. Results were obtained from investigations performed in the presence of a generated electric field with controlled variable characteristics, and in the presence of an electric field generated by a tramline. The analysis of measurement registers was performed using Short‐Time...
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Suppression of Supply Current Harmonics of 18-Pulse Diode Rectifier by Series Active Power Filter with LC Coupling
PublicationThe reported research aims at improving the quality of three-phase rectifier supply currents. An effective method consists of adding properly formed booster voltages to the fundamental supply voltages using a series active filter. In the proposed solution, the booster voltages are generated by three single-phase systems consisting of inverters, LC filters, and single-phase transformers. The application of LC couplings ensures low...
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Enhancing seismic performance of rigid and semi-rigid connections equipped with SMA bolts incorporating nonlinear soil-structure interaction
PublicationNowadays, using smart connections can improve the performance of buildings with some recentering features that are from the superelastic behavior of Shape Memory Alloys (SMAs). It seems that there is different rigidity between the designed connection and the real one in Steel Moment-Resisting Frames (SMRFs), which can be considered as a problematic issue due to the importance of connections in seismic performance assessment. This...
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Satellite Laser Ranging technique as a tool for the determination of the Schwarzschild, de Sitter and Lense-Thirring effects
PublicationSatellite Laser Ranging (SLR) is a modern technique used in various research areas and applications related to geodesy and geodynamics. It is commonly used for tasks such as establishing the International Terrestrial Reference Frame (ITRF), monitoring Earth Orientation Parameters (EOP), determining the geocenter, measuring fundamental physical constants, calibrating microwave tracking techniques, conducting time transfer experiments,...
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Redukcja czasu analizy MZP przez ograniczenie rozmiaru rozwiązania
PublicationAnaliza drzew niezdatności jest uznaną metodą analizy bezpieczeństwa systemów. Notacja ECSDM pozwala definiować zależności czasowe między zdarzeniami drzewa oraz przeanalizować je w celu określenia zależności pomiędzy zdarzeniami z Minimalnych Zbiorów Przyczyn (MZP). Dzięki wprowadzeniu klasyfikacji zdarzeń z MZP można wyodrębnić zależności czasowe istotne dla zapobiegania wywoływania hazardu przez konkretny MZP. Pozostałe zależności...
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Mobilny system do detekcji obiektów ferromagnetycznych z magnetometrami pompowanymi optycznie
PublicationW pracy przedstawiono mobilny system do detekcji obiektów ferromagnetycznych. Każdy obiekt ferromagnetyczny zaburza w swoim otoczeniu równomierność pola magnetycznego Ziemi. Zaburzenie to może być zmierzone za pomocą precyzyjnych magnetometrów. W prezentowanym mobilnym systemie zastosowano magnetometry pompowane optycznie pracujące w układzie różnicowym. W pracy opisano magnetometryczny system do detekcji obiektów ferromagnetycznych,...
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Niekorzystny wpływ przekształtnikowego zasilania PWM na silniki asynchroniczne trakcyjne
PublicationThe electric traction drives with an AC motor fed by a frequency converter are used more and more often nowadays. The most significant side effects, of a converter's output voltage forming PWM method for AC motor windings, are steep voltage changes, which can initiate several destructive phenomena. The paper presents the adverse influence of a converter common mode voltage on the motor windings' increased voltage exposure and the...
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Destructive impact of PWM inverters on traction AC motors
PublicationThe electric traction drives with an AC motor fed by a frequency converter are used more and more often nowadays. The most significant side effects, of a converter's output voltage forming PWM method for AC motor windings, are steep voltage changes, which can initiate several destructive phenomena. The paper presents the adverse influence of a converter common mode voltage on the motor windings's increased voltage exposure and...
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Quality assessment of high voltage varistors by third harmonic index
PublicationHigh voltage varistors that consist of grained ZnO have to be tested before assembling into a surge arrester. The existing methods demand a usage of high voltages and intensive currents that is inconvenient, destructive and needs extensive power consumption. Additionally, these methods require metallization of the prepared varistor structures that increases costs. We propose another method of varistors quality assessments by a...
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Destructive Consequences of PWM Inverter Feeding for Traction AC Motors
PublicationThe electric traction drives with an AC motor fed by a frequency converter are used more and more often nowadays. The most significant side effects, of a converter's output voltage forming PWM method for AC motor windings, are steep voltage changes, which can initiate several destructive phenomena. The paper presents the adverse influence of a converter common mode voltage on the motor windings' increased voltage exposure and the...
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Estimation of interior-permanent-magnet-synchronous-motor rotor position by analysis of phase-current derivatives
PublicationThis paper describes an algorithm for estimation of IPMSM rotor angular position. The algorithm uses derivatives of motor phase currents resulting from PWM modulation to obtain the rotor position. The presented method is designed for medium- and high-speed range, since it is based on determination of the EMF vector. Calculation of the motor position is performed in every PWM cycle. The standard SV-PWM method is used to determine...