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Wyniki wyszukiwania dla: POLYPHASE MOTORS, POLYPHASE DRIVES, POWER-SUPPLY ASYMMETRY, MOTOR ASYMMETRY, TORQUE RIPPLES, PHASE-LOAD DISTRIBUTION
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Influence of Shunt Compensation with SVC Devices on Resonance Risk in Power Systems
PublikacjaMany analyses are required to locate a new reactive power source in a power system. The choice of a location is a very complex matter which requires various aspects to be considered. Selecting a location also entails the necessity to assess it from the point of view of the selected compensator’s structure as well as the system’s performance in various states with the new device on. The paper presents the issues of assessing compensator...
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Investigation of the vertical distribution of the sound speed of the Gulf of Gdansk in the years 2000-2010
PublikacjaThe conditions of the acoustic wave propagation in the southern Baltic are much more complex than in other shallow waters. In the typical shallow water, seasonal changes in acoustical conditions in the upper layer, of the depth of about 60-70 m, are observed. They are caused by variation of the annual meteorological conditions. Most often, in the deep water layer, acoustical conditions are stable throughout the year. However, in...
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Phase separation in poly(butylene terephthalate)-based materials prepared by solid-state modification
PublikacjaThe morphology of a series of poly(butylene terephthalate) (PBT)/fatty acid dimer diol (FADD)-based copolyesters prepared by solid-state modi fi cation (SSM) was studied. It was shown that in copolyesters containing less than 10 wt% FADD two different phases, i.e. a PBT crystalline phase and a PBT-rich amorphous phase, are present. The FADD residues were more or less homogeneously distributed throughout the interlamellar regions....
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Optimizing CO2 Purification in a Negative CO2 Emission Power Plant
PublikacjaIn the pursuit of mitigating CO2 emissions, this study investigates the optimisation of CO2 purification within a Negative CO2 Emission Power Plant using a spray ejector condenser (SEC) coupled with a separator. The approach involves direct-contact condensation of vapour, primarily composed of an inert gas (CO2), facilitated by a subcooled liquid spray. A comprehensive analysis is presented, employing a numerical model to simulate...
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O strumieniu mocy w silniku lub w układzie napędowym
PublikacjaW silniku lub w układzie napędowym wielkość strumienia mocy rośnie w kierunku przeciwnym do kierunku przepływu mocy. Straty energetyczne i sprawność energetyczna silnika lub układu napędowego powinny być przedstawiane jako funkcje wielkości fizycznych niezależnych od strat. Takimi wielkościami są prędkość i obciążenie silnika. Jednakże obraz strumienia mocy w silniku lub w układzie napędowym jest przedstawiany w literaturze w formie...
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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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Advanced sensitivity analysis of the impact of the temporal distribution and intensity of rainfall on hydrograph parameters in urban catchments
PublikacjaKnowledge of the variability of the hydrograph of outflow from urban catchments is highly important for measurements and evaluation of the operation of sewer networks. Currently, hydrodynamic models are most frequently used for hydrograph modeling. Since a large number of their parameters have to be identified, there may be problems at the calibration stage. Hence, sensitivity analysis is used to limit the number of parameters....
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Event-Triggered Communication in Cooperative, Adaptive Model Predictive Control of a Nuclear Power Plant’s Turbo–Generator Set
PublikacjaThis paper discusses the issue of optimizing the communication between the components of a cooperating control system formed by a pair of MPC controllers of a nuclear power plant turbine set using online recursive least squares identification. It is proposed to use event-triggered communication, i.e., sending information only at selected time instants, as opposed to the standard approach where communication is triggered by time...
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Nonlinear model of a synchronous generator for analysis of more electric aircraft power systems
PublikacjaA nonlinear model for studying a variable-speed synchronous generator (SG) in more electric aircraft (MEA) power system has been developed. The saturation effects of the SG magnetic circuit have been considered. The model has been implemented in the Synopys/Saber simulation environment. The modelling language MAST has been used to elaborate the SG model. The model exhibit a network with the same number of external terminals/ports...
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Possibility to use engine compression ignition engines in floating power plants marine
PublikacjaCompression-ignition engines used in ship technology as main propulsion engines are large units reaching even to 50-60 MW. The engines can be used in power industry for electricity generation in a simple or combined steam turbine system in combined heat and power plants. The leading engine in such an arrangement is an internal-combustion piston engine. The main propulsion engines are used in large piston internal-combustion engines...
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Numerical modeling of PFAS movement through the vadose zone: Influence of plant water uptake and soil organic carbon distribution
PublikacjaIn this study, we investigated the effects of soil organic carbon (SOC) distribution and water uptake by plant roots on PFAS movement in the vadose zone with a deep groundwater table under temperate, humid climate conditions. Two series of numerical simulations were performed with the HYDRUS computer code, representing the leaching of historical PFOS contamination and the infiltration of water contaminated with PFOA, respectively. We...
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Static Series and Shunt-series PE Voltage-quality Controllers
PublikacjaAs presented in the Chap. 7 static shunt power electronics (PE) voltage-quality controllers protect the utility electrical system from the unfavorable impact of customer loads. Shunt controllers, as shown in Chap. 6, are recommended mainly for mitigation of the causes of disturbances, and not their effects in distanced nodes of a power-electronics system. In the case when reduction of disturbances effects is required, which leads...
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Simplified, multiregional fuzzy model of a nuclear power plant steam turbine
PublikacjaPower systems, including steam turbines and synchronous generators, are complex nonlinear systems with parameters varying over time. The paper presents the developed simplified, multiregional fuzzy model of the steam turbine of a nuclear power plant turbine generator set and compares the results with a full nonlinear model and commonly used linear input-output model of a steam turbine. The proposed model consist of series of linear...
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The concept of a new two-stage fuse for high power pulse forming
PublikacjaThis manuscript introduces the concept, physical operating principle and studies on a new and unique two stage forming fuse (TSFF) with interstage spark gap commutation and presents its application for forming high power pulses of extreme parameters. The paper classifies TSFF performance and compares it with conventional single-stage forming fuses. The conclusions are supported by analytical and experimental studies in laboratory...
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Photovoltaic Maximum Power Point Technique based on Incremental Conductance (INCON) control algorithm
PublikacjaMaximum output power status can significantly improve the deployment rate of solar energy system. In order to get the maximum power output, issue of tracking maximum power point (MPP), reduced harmonics around MPP and improve efficiency of the solar power energy system, this paper presents the improved maximum power point tracking (MPPT) control...
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DIFFRACTION PHASE MICROSCOPY FOR OBSERVATION ON RED BLOOD CELLS FLUCTUATION
PublikacjaNowadays there is quite huge need for more and more precise and effective fast diagnostics methods in hematology diseases. One of the most important blood components are erythrocytes – RBCs (Red Blood Cells). Due to their size they are easy to observe using microscopy. It is commonly known that the shape and lifetime of RBCs allows for early disease identification. Authors present special measurement system for RBCs fluctuations observation...
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Study of Phase and Chemical Composition of Bi1-xNdxFeO3 Powders Derived by Pressureless Sintering
PublikacjaIn the present paper studies on Bi1xNdxFeO3 for x =0.1-0.4 are reported. The mixed oxide method followed with pressureless sintering was employed for ceramics fabrication. Thermal behavior of stoichiometric mixtures of simple oxide powders, viz. Bi2O3, Nd2O3 and Fe2O3 was studied by simultaneous thermal analysis. It was found that with an increase in neodymium content the weight loss increased from 0.75% to 3.16% for x =0.1 and...
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High power, medium voltage, modular active power filtering system
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Control of a wind power generator in case of voltage sags in power network
PublikacjaW artykule poruszono problem związany ze sposobem sterowania generatorem elektrowni wiatrowej w przypadku wystąpienia po stronie sieci zapadów napięcia.Jako generator wykorzystano maszynę dwustronnie zasilaną której stojan podłączono bezpośrednio do sieci natomiast wirnik zasilano poprzez kaskadę przekształtników. Wystąpienie spadku lub zapadu napięcia sieci w przypadku pracy tego typu generatora może doprowadzić do uszkodzenia...
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Cogenerative micro power plants - a new direction for development of power engineering?
PublikacjaW pracy przedstawiono rozważania dotyczące perspektywy mikrosiłowni domowych w gospodarce rozproszonej. Przedstawiono oryginalne kryterium doboru czynnika roboczego w mikrosiłowni oraz przedstawiono sprawności cieplne i egzergetyczne obiegów Clausiusa-Rankina realizujących pracę mikrosiłowni.
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Sea surface temperature distribution during upwelling along the Polish Baltic coast
PublikacjaAmong over 150 maps of sea surface temperature in the Polish Baltic coastal region derived from satellite data during the warm period of the year (April-October) in 2000-2002, 41 cases were noted where its distribution showed characteristic features indicating the occurrence of coastal upwelling. The fundamental parameters of range, probability of occurrence and temperature modification caused by water from deeper sea layers...
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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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Thermodynamic Cycles of Air Microturbine Power Plants Working on Biomass Fuels
PublikacjaThe gas turbine engine is modified to work as an air turbine set which consists, in the simplest arrangement, of a compressor, a heat exchanger and a turbine. Air is a working medium for both: the compressor and the turbine. This kind of air turbine set can be applied in power plants working on biomass fuels. In this solution we can burn fuels of varying parameters in the external combustion chamber without any harmful effects...
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Compact broadband multi-way 1:6 power divider
PublikacjaThis paper introduces a design flow of a microstrip multi-way 1:6 power divider incorporating photonic bandgap (PBG) structures. Themethod proposed has enabled the achievement of considerable miniaturization (15%) together with transmission characteristics enhancement(141% bandwidth). Measured results show significant similarity to theoretical characteristics, which proves the attractiveness of presented design methodology.
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HIERARCHICAL CYCLES IN MODERN POWER SYSTEMS – EXERGY ANALYSIS UNDER PART LOADS
PublikacjaThe aim of the paper is to investigate thermodynamic efficiency of advanced hierarchic power cyclesunder partial loads by using of exergy analyze. Advanced hierarchical power systems arecomposed of few energy conversion cycles, most common are steam and gas cycles in various configurations, but they may contain fuel cells, ORC, lithium bromide absorption chillers and others. Moreover hierarchical cycles can be powered by several...
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Performance analysis of power swing blocking feature in ABB 670 series impedance relays
PublikacjaThis 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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Numerical single-phase modeling of turbulent flow and heat transfer of nanofluids
PublikacjaIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (6 000< Re < 12 000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with published experimental data.
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Market Structure and Market Power in Selected Sectors of The Polish Economy Based on COICOP Classification
PublikacjaThis paper present new and simple measures of market structure and market power. Based on the classical models of market structures, where a given structure is determined by the number of enterprises, indexes of degree of monopoly have been estimated, representing an average number of entities per branch. Additionally, market power indexes have been determined as an average revenue per an enterprise in a given branch. This approach...
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Performance/energy aware optimization of parallel applications on GPUs under power capping
PublikacjaIn the paper we present an approach and results from application of the modern power capping mechanism available for NVIDIA GPUs to the bench- marks such as NAS Parallel Benchmarks BT, SP and LU as well as cublasgemm- benchmark which are widely used for assessment of high performance computing systems’ performance. Specifically, depending on the benchmarks, various power cap configurations are best for desired trade-off of performance...
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HYBRID ENERGY SYSTEM FOR A CLASSIC SHIP POWER PLANT
PublikacjaThe article presents a brief overview of hybrid energy systems used on ships. The area of their application is outlined. The benefits of using such systems are also indicated. Then, the classic ship power plant is defined. The most important part of the article is a proposal how to modify a classic engine room by using a hybrid energy system. The idea is: to accumulate a part of electricity in areas where it is allowed to burn...
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Determination of leakage inductances of multi-winding and single-phase transformer
PublikacjaThis paper presents the method for determination of leakage inductances of single-phase and multi-winding transformer. The matrix of leakage inductances takes into account leakage self and also leakage mutual magnetic couplings. It is assumed that there is a flux common to all windings and several leakage fluxes referred to a particular winding. The flux linkages of each coil needed fo calculation of leakage inductances was computed...
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Monitoring of Chlorine Concentration in Drinking Water Distribution Systems Using an Interval Estimator
PublikacjaThis paper describes the design of an interval observer for the estimation of unmeasured quality state variables in drinking water distribution systems. The estimator utilizes a set bounded model of uncertainty to produce robust interval bounds on the estimated state variables of the water quality. The bounds are generated by solving two differential equations. Hence the numerical efficiency is sufficient for on-line monitoring...
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Do morphometric parameters and geological conditions determine chemistry of glacier surface ice? Spatial distribution of contaminants present in the surface ice of Spitsbergen glaciers (European Arctic)
PublikacjaAbstract The chemism of the glaciers is strongly determined by long-distance transport of chemical substances, and their wet and dry deposition on the glacier surface. This paper concerns spatial distribution of metals, ions, and dissolved organic carbon, as well as the differentiation of physicochemical parameters (pH, electrical conductivity) determined in ice surface samples collected from four Arctic glaciers during the summer...
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Design of power cable lines partially exposed to direct solar radiation – special aspects
PublikacjaPower cable lines are usually buried in the ground. However, in some cases, their ending sections are mounted along the supports of overhead lines. This leads to a situation where the cables are exposed to direct solar radiation and, consequentially, overheat. The paper presents the advanced computer modelling of power cables’ heating, considering their insolation as well as the effect of wind. The temperature and current-carrying...
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Optimised Allocation of Hard Quality Sensors for Robust Monitoring of Quality in Drinking Water Distribution Systems
PublikacjaA problem of optimised placement of the hard quality sensors in Drinking Water Distribution Systems for robust quality monitoring is formulated. Two numerical algorithms to solve the problem are derived. The optimality is meant as achieving a desired trade off between the sensor capital and maintenance costs and resulting robust estimation accuracy of the monitoring algorithm. The robust estimation algorithm recently developed...
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Two-phase flow in heterogeneous porous media with non-wetting phase trapping
PublikacjaThis article presents amathematical model describing flowof two fluid phases in a heterogeneous porous medium. Zaproponowano model matematyczny przepływu dwufazowego w drobnoziarnistym ośrodku porowatym zawierającym inkluzje gruboziarniste. Inkluzje charakteryzują się niższą wartością ciśnienia wejścia dla płynu niezwilżającego (np. powietrze, ropa naftowa) niż materiał podstawowy. Podczas nawadniania takiego ośrodka dochodzi do...
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Inlet air fogging of marine gas turbine in power output loss compensation
PublikacjaThe use of inlet air fogging installation to boost the power for gas turbine engines is widely applied in the power generation sector. The application of fogging to mechanical drive is rarely considered in the literature [1]. This paper will cover some considerations relating to its application to gas turbines in ship drive. There is an important evaporative cooling potential throughout the world when the dynamic data is evaluated,...
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Sinusoidal Control of a Brushless DC Motor with Misalignment of Hall Sensors
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Non-linear control of induction motor in field weakening region
PublikacjaW referacie przedstawiono układ sterowania silnikiem asynchronicznym klatkowym, oparty na modelu multiskalarnym. Dla zaproponowanej struktury wybrano dwa wektory do transformacji zmiennych stanu: wektor prądu stojana i wektor strumienia stojana. Przepro¬wadzono badania eksperymentalne na stanowisku badawczym z silnikami indukcyjnymi o mocy 22kW, w których do odtwarzania prędkości kątowej wykorzystano obserwator prędkości kątowej...
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Properties of control systems based on nonlinear models of the induction motor.
PublikacjaW artykule przedstawiono zastosowanie obserwatora prędkości kątowej wirnika silnika indukcyjnego w nielinowych układach regulacji. Porównano dwa typy układów sterowania multiskalarnego. Przedstawiono przypadek niestabilnej pracy układu nieliniowego sterowania za pomocą symulacji komputerowej.W artykule przedstawiono dwa układy sterowania silnikiem asynchronicznym klatkowym, zasilanym z falownika napięcia, oparte na modelu multiskalarnym,...
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Output filter for voltage source inverter supplying induction motor
PublikacjaW artykule przedstawiono problemy związane z występowaniem składowej zerowej w falowniku napięcia. Jako rozwiązanie zastosowano filtr bierny składowej zerowej dodatkowo pełniący funkcję filtru sinusoidalnego. Filtr nie wprowadza zauważalnych przesunięć prądów i napięć na wejściu i wyjściu układu. Przedstawiono metodę doboru elementów filtru w prostokatnym układzie współrzędnych oraz wyniki badań symulacyjnych i eksperymentalnych....
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Measuring system for analysis of motor supplying current for diagnostic purposes
PublikacjaProblemy, jakie pojawiają się przy interpretacji wyników pomiarów prądu silnika dla celów diagnostycznych wynikają z różnicy częstotliwości składowych obliczonych teoretycznie i uzyskanych w badaniach eksperymentalnych. W przedstawionym systemie pomiarowym problem ten rozwiązano w ten sposób, że pomiar częstotliwości sieci zasilającej i prędkości obrotowej jest wykonywany w tym samym przedziale czasowym, co pomiar składowych widma.
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Main inductances of induction motor for diagnostically specialized mathematical models
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Measurements and Analysis of Motor Supplying Current Waveform for Diagnostic Purposes
PublikacjaPodano proponowaną metodę diagnostyki łożysk tocznych w silnikach indukcyjnych poprzez pomiar i analizę prądu zasilającego. Przedstawiono opracowany system pomiarowy oraz wyniki badań na łożyskach o specjalnie wprowadzonych uszkodzeniach.
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Speed observer system for advanced sensorless control of induction motor.
PublikacjaW pracy przedstawiono obserwator prędkości silnika asynchronicznego zastosowany w układzie sterowania ze zmiennymi multiskalarnymi oraz regulatorem predykcyjnym prądu. Zawarto wyniki badań symulacyjnych i eksperymentalnych.
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Graphomotor functions in ADHD – motor or planning deficit? A microgenetic approach
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Artificial neural network based sensorless control ofinduction motor.
PublikacjaW artykule przedstawiono bezczujnikowy układ sterowania silnikiem indukcyjnym wykorzystujący sztuczne sieci neuronowe (ANN). Sieć neuronową wykorzystano w regulatorze prędkości silnika. Zaprezentowano wyniki badań symulacyjnych.
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The choice of parameters of induction motor model using a genetic algorithm.
PublikacjaRozważano problem doboru parametrów modeli matematycznych dużych 3 -fazowych silników indukcyjnych. Modele o prawidłowo dobranych parametrach mogą być pomocne podczas procedur projektowych. Podane silniki mogą być używane jako napędy sterów strumieniowych statków. Symulacje w środowisku Matlab, uwzględniają modele statyczne silników. Parametry silników dobierane są za pomocą przybornika Genetic Algorithm Toolbox. Skuteczność metody...
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Sensorless control of high speed permanent-magnet synchronous motor
PublikacjaW artykule przedstawiono metodę bezczujnikowego sterowania szybkoobrotowym silnikiem z magnesami trwałymi. Pokazano działanie układu sterowania opartego na filtrze kalmana (EKF) jako obserwatora prędkości obrotowej.
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Asynchronous motor nonlinear control with inverter output LC filter
PublikacjaFiltr wyjściowy falownika jest stosowany w napędach elektrycznych prądu przemiennego o regulowanej prędkości w celu wygładzenia przebiegów prądów i napięć zasilających silnik. Zastosowanie filtru utrudnia realizację precyzyjnych metod sterowania silnikami, szczególnie w przypadku napędów bezczujnikowych (tj. bez czujnika prędkości obrotowej wału silnika). Ponieważ, ze względów praktycznych, nie stosuje się pomiarów prądów i napięć...