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Wyniki wyszukiwania dla: dynamics of pneumatic drive
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Calculation of self and mutual inductances of the switched reluctance machine mathematical model.
PublikacjaA mathematical model of the switched reluctance machine (SRM) in a drive system obtained using Lagrange's energy method and a method of calculation of self and mutual inductances of the SRM are presented in the paper. The self and mutual inductances are elements of Lagrange's function in generalised coordinates and have been calculated using the finite element method (FEM). Selected calculation results for the particular machine...
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Medium voltage drives - challenges and requirements
PublikacjaThe design and application of medium voltage (MV) drives are associated with different requirements related to the line side and motor side of the drive. This paper presents a brief review of the existing challenges and requirements for employing medium voltage drives in various industries. Line side, motor side, and converterproblems and requirements are described. The aim of the paper is to review the existing problems to allow...
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Optimized Space-Vector Modulation Schemes for Five-Phase Precision Low-Speed Drives with Minimizing the Stator Current Ripple
PublikacjaOne of the main ways to improve the quality of a precision electric drive is minimization of the stator current pulsations generated by the voltage inverter. The solution of this problem can be achieved by using of multiphase inverters, as well as improving control algorithms. This paper considers the influence of the space-vector modulation algorithm with different switching sequences of basic vectors on the stator current pulsations...
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Cosmic-Time Quantum Mechanics and the Passage-of-Time Problem
PublikacjaA new dynamical paradigm merging quantum dynamics with cosmology is discussed.
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On finite element modelling of architectural fabrics for hanging roofs
PublikacjaArtykuł dotyczy modelowania konstytutywnego i identyfikacji parametrów materiałowych dla tkanin technicznych powszechnie stosowanych w konstrukcjach membranowo-cięgnowych. Autorzy przedstawiają krótką charakterystyke modeli stosowanych w opisie zachowania sie tkanin technicznych. Opisano metodę do idetyfikacji nieliniowo-sprężystych właściwości tkanin technicznych. Dodatkowo dokonao porówania wyników z prób jednoosiowego rozciągania...
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Identification of nonlinear viscoelastic properties of the ''Panama'' fabric
PublikacjaTkanina techniczna Panama wytwarzana przez firmę Sattler (Niemcy)wykazuje cechy nieliniowe w tym właściwości lepkosprężyste w czasie testów długoterminowych. Na podstawie jednoosiowych testów płynięcia i regeneracji przeprowadzonych dla pięciu poziomów obciążenia przeprowadzono identyfikacje nieliniowych lepkosprężystych właściwości tkaniny. Do opisu zależności konstytutywnych użyto całkowego modelu Schapery'ego. Zastosowano funkcję...
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Identification of inertia, damping and stiffness parameters for low pressure steam turbine framework.
PublikacjaW pracy przedstawiono metodę identyfikacji masy tłumienia i sztywności kadłuba części niskoprężnej turbiny parowej 200MW.
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Symbolic multibody models for digital-twin applications
PublikacjaSymbolic generation of multibody systems equations of motion appeared in the 1980s. In addition to their computational advantage over their numerical counterparts, symbolic models can be very easily and straightforwardly interfaced with a wide range of software environments and hardware devices. These two features place this approach in a pole position to participate and intervene in the design of digital twins for systems such...
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Rheological Problems of Technical Fabirc
PublikacjaW pracy przedstawiono wyniki identyfikacji modeli Chaboche'a i Schapery dla tkaniny technicznej Panama.
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Methods of material parameters identification for isotropic damage in viscoplastic flow conditions
PublikacjaW pracy zaprezentowano trzy metody identyfikacji parametrów materiałowych dla izotropowego zniszczenia w warunkach lepkoplastycznego płynięcia. Przedstawiono wyniki identyfikacji dla dwóch stopów aluminium, które następnie zweryfikowano porównując wyniki symulacji numerycznych z wynikami eksperymentalnymi.
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Experimental research on technical fabric of the Forest Opera Roof in Sopot
PublikacjaThe experimental analysis of the technical fabric Valmex is presented. The study involves uniaxial tensile, cyclic, rheological and biaxial tests. Some of the main differencies between two types of the analysed material have been identified. Mechanical properties of the textile have been modeled by the viscoelastic standard model with quite good effect.
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Constructional properties of polycarbonate plates for EURO 2012 Gdansk stadium
PublikacjaPrzedstawiono wyniki badań doświadczalnych dla płyt z poliwęglanu litego, które miały zostać wykorzystane jako materiał konstrukcyjno-osłonowy stadionu piłkarskiego na mistrzostwa Euro 2012 w Gdańsku. Zidentyfikowano moduł Younga oraz Poissona, wykonano próby cykliczne oraz pełzania. Właściwości mechaniczne poliwęglanu litego oceniono jako dobre, choć obawy budzą mikrorysy pojawiające się podczas badań w strukturze materiału.
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Regression points in non-intrusive polynomial chaos expansion method and D-optimal design
PublikacjaThe paper addresses selected issues of uncertainty quantification in the modelling of a system containing surgical mesh used in ventral hernia repair. Uncertainties in the models occur e.g. due to variability of abdominal wall properties among others. In order to include them, a non-intrusive regression-based polynomial chaos expansion method is employed. Its accuracy depends on the choice of regression points. In the study a relation...
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Drivetrain of a Wind Turbine
PublikacjaIn a most commonly met design of a wind turbine the power is transmitted from the rotor to the generator through the system composed of the main shaft, friction connection, multiplying gearbox and a flexible coupling. The driving system comprises almost a complete set of the machine elements being described during machine design lectures and can serve as an interesting illustration...
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Novel method of estimation of inertial and dissipative parameters of a railway pantograph model
PublikacjaAn increase in electric railway vehicles service velocity requires that correct interaction between the pantograph and the catenary is ensured. This implies the need for developing mathematical models of pantographs and catenaries and determining their parameters. The article presents a method to determine parameters of mechanical joints of a railway pantograph based on analysis of pantograph subassemblies in swinging motion. The...
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On various modelling approaches to real-time visualisation of blood flow
PublikacjaThis paper reviews various modelling approaches to real-time visualisation of blood flow. These include classic, macroscale approach based on the momentum conservation equation together with a proper constitutive equation. Moreover, modern micro- and mesoscale approaches, such as molecular dynamics and dissipative particle dynamics, are discussed. Advantages and disadvantages of the discussed methods are highlighted with particular...
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Numerical modelling of moored floating structures using SPH. Preliminary results
PublikacjaThis article presents partial results of the works carried out under the research project "The development of the methodof modeling the dynamics of the floating (offshore) objects subjected to the environment influence", which aims at developing computational methods for modeling the dynamics of offshore structures.The article contains the description of the method of modeling the hydrodynamic impacts using SPH method and the description...
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Modeling of Common Mode Currents Induced by Motor Cable in Converter Fed AC Motor Drives
PublikacjaInvestigation of conducted EMI generation in AC motor fed by pulse width modulated frequency converters requires to consider parasitic capacitances in converters, motor windings and feeding cables to be taken into account. Motor voltage transients and related common mode currents are significantly correlated with resonance effects occurring in load circuits. An analysis of frequency converter load impedance-frequency characteristics...
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A unified approach to the analysis of electric energy and fuel consumption of cars in city traffic
PublikacjaForecasting fuel and electricity consumption is an important factor determining the direction of changes in road engineering solutions, traffic management, selection of routes for public transport and development more efficient car drive systems. With a reliable and easy-to-use computational tool, it is possible to reduce the consumption of primary energy sources and reduce the emission of toxic compounds in cities. An analysis...
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Study of the effect of adiabatic heating on the operation of the electrodynamic actuator
PublikacjaElectrodynamic actuators are used in hybrid switching systems where a very quick contact separation as well as operation repeatability and long-term reliability are required. The article presents selected results of thermal studies in the electrodynamic drive system. Study was carried out on the basis of the 3D electromagneto-thermal model implemented in the Ansys_Maxwell environment. The present model allows to determine the critical...
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Analysis and characterization of coordination compounds by resonance Raman spectroscopy
PublikacjaResonance Raman spectroscopy has become a powerful tool to study excited-state geometries, excited-state charge distributions and photoinduced reaction dynamics in coordination compounds. Due to their rich photophysical properties coordination compounds are utilized for a variety of applications ranging from DNA sensing to photocatalysis. This review features recent applications of various resonance Raman scattering techniques...
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Analysis of Rolling Resistance of Tires With Run Flat Insert
PublikacjaRun flat properties are required for tires intended for special applications like military or rescue vehicles. Run-Flat inserts make possible to drive a car or truck, with certain restrictions, also when inflation pressure is very low or non-existing (after tire damage). Rolling resistance of tires rolling the inserts increases considerably in relation to the rolling resistance of properly inflated tires. This paper presents results...
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Hierarchical dissolved oxygen control for activated sludge processes
PublikacjaA hierarchical controller for tracking the dissolved oxygen reference trajectory in activated sludge processes is proposed and investigated. The removal of nitrogen and phosphorous from wastewater is considered. Typically, an aeration system itself is a complicated hybrid nonlinear dynamical system with faster dynamics compared to the internal dynamics of the dissolved oxygen in a biological reactor. It is a common approach to...
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Broken Rotor Symptons in the Sensorless Control of Induction Machine
PublikacjaInverter fed sensorless controlled variable speed drives with induction machine are widely used in the industry applications, also in wind power generation and electric vehicles. On-line self diagnostic systems implementation is needed for early stage fault detection and avoiding a critical fault. Diagnostic algorithms in modern DSP-based controllers can operate simultaneously with control system functions. In the closed-loop controlled...
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Reputacja i zaufanie w systemach teleinformatycznych z podmiotami anonimowymi podejście dynamiczne
PublikacjaAbstrakcją współczesnego systemu teleinformatycznego jest system wieloagentowy z autonomicznymi, racjonalnymi i wirtualnie anonimowymi agentami wchodzącymi we wzajemne interakcje dla wymiany usług. W referacie uzasadniono konieczność projektowania dla niego podsystemu budowy reputacji i zaufania oraz odpowiednich analiz w ujęciu dynamicznym. Dokonano przeglądu motywacyjnie zgodnych mechanizmów uczciwego raportowania usług oraz...
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Firing map for periodically and almost-periodically driven integrate-and-fire models: a dynamical systems approach
PublikacjaWe consider the Leaky Integrate-and-Fire and Perfect Integrator models of neuron’s dynamics with the input function being periodic and almost-periodic (in the sense of Stepanov). In particular we analyze properties and dynamics of the so-called firing map, which iterations give timings of consecutive spikes of a neuron. In case of a periodic input function we provide a detailed description of the sequence of interspike-intervals,...
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A Simplified SVPWM Technique for Five-leg Inverter with Dual Three-phase Output
PublikacjaThis article proposes a simplified space vector pulse-width modulation (SVPWM) technique five-leg inverter with dual three-phase output. An idea to fed the dual tree-phase machine by the multiphase voltage source inverters (VSIs) is not new. Dual- and multi-motor drive systems are widely used in the industry applications. The most popular fields are: electric vehicles (EVs) and traction systems. Moreover, the specific characteristic...
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Napęd z silnikiem indukcyjnym i 4-gałęziowym falownikiem SiC do turbosprężarek powietrza ogniw paliwowych dużej mocy
PublikacjaWysoka cena ogniw paliwowych utrudnia ich szerokie zastosowanie w transporcie i przemyśle. Należy szukać możliwości obniżenia ich kosztu również poprzez obniżenie kosztu i zwiększenie wydajności urządzeń pomocniczych ogniwa paliwowego (Balance of the Plant). Autorzy proponują aby w napędzie sprężarki powietrza, zastosować wysokoobrotowy silnik indukcyjny, który jest tańszy od stosowanych obecnie silników PMSM. W referacie zaproponowano...
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Metrological analysis of an computerized system of protection against electric shock in circuits with variable speed drives
PublikacjaDrive systems, that can be operated at variable speed, are equipped with power electronics converters. This causes distortion of the earth current, and consequently the need to take into account the use of proper protective devices in relation to earth current harmonics. This paper presents a system for protection against electric shock in circuits with power electronics converters and metrological analysis indicating the requirements...
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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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Errors of a Linear Current Approximation in High-Speed PMSM Drives
PublikacjaCurrent sampling techniques and predictive algorithms used in the digital control of electric drives rely on a simple mathematical model that assumes linear current changes upon constant supplying voltages. This paper identifies rotor movement as a factor that makes this assumption invalid when the rotor covers an angular distance of a few tens of degrees during the control interval duration. The errors of the linear current approximation...
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Fitting the mobile device characteristics to the user's hearing preferences
PublikacjaA method for fitting the mobile computer audio characteristics to the user's hearing preferences is proposed. The process consists of two stages: calibration and dynamics processing. During the calibration phase the user performs a loudness scaling test giving their response regarding the perceived loudness. The dynamics processing made on above basis sets the loudness to the most comfortable level. The processing accounts both...
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A first-principles study of electron attachment to the fully hydrated bromonucleobases
PublikacjaDegradation mechanism of four brominated nucleobases (BrX), potential DNA radiosensitizers, is studied in explicit water solution, using ab initio molecular dynamics. Several fs long dynamics is needed to localize an electron on the nucleobase. Produced by electron attachment BrX anion radical degrades through the bromide anion abstraction, barrier-free (purines) or with low barrier (pyrimidines), to a reactive nucleobase radical....
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Dynamic Signature Vertical Partitioning Using Selected Population-Based Algorithms
PublikacjaThe dynamic signature is a biometric attribute used for identity verification. It contains information on dynamics of the signing process. There are many approaches to the dynamic signature verification, including the one based on signature partitioning. Partitions are the regions created on the basis of signals describing the dynamics of the signature. They contain information on the shape of the signature characteristic of a...
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Anti-plane waves in an elastic thin strip with surface energy
PublikacjaWe consider anti-plane motions of an elastic plate taking into account surface energy within the linear Gurtin–Murdoch surface elasticity. Two boundary-value problems are considered that describe complete shear dynamics of a plate with free faces or with free and clamped faces, respectively. These problems correspond to anti-plane dynamics of an elastic film perfectly or non-perfectly attached to a rigid substrate. Detailed analysis...
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Broadband Modeling of Motor Cable Impact on Common Mode Currents in VFD
PublikacjaExamination of conducted EMI generation and propagation in AC motor drives fed by frequency converter requires to consider parasitic capacitances in converters, motor windings and feeding cables to be taken into account. AC motor winding voltage transients and related common mode currents are significantly correlated with resonance effects occurring in converter's load circuits. Intensity levels of these phenomena depend...
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Medium-Voltage Drives: Challenges and existing technology
PublikacjaThe article presents an overview of state-of-art solutions, advances, and design and research trends in medium-voltage (MV) drive technologies - and also discusses the challenges and requirements associated with the use of such drives. The choice and deployment of MV drives in industries are associated with numerous requirements related to the front-end converter (grid side) and inverter (machine side). The focus is on solutions...
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An intelligent cellular automaton scheme for modelling forest fires
PublikacjaForest fires have devastating consequences for the environment, the economy and human lives. Understanding their dynamics is therefore crucial for planning the resources allocated to combat them effectively. In a world where the incidence of such phenomena is increasing every year, the demand for efficient and accurate computational models is becoming increasingly necessary. In this study, we perform a revision of an initial proposal...
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Application of road map of operating condition for estimation of fuel and electric energy consumption from city transport
PublikacjaThe paper presents procedure of data collecting and generation of road map of operating condition in the selected urban area. This map allows forecasting the selected vehicle operating parameters for the assumed road. The main parameters calculated using the road maps of operating conditions are: total energy spent to drive the selected vehicle, consumed fuel, travel time, average speed of travel, CO2 emissions. Presented example...
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Wpływ błędów parametrów modelu maszyny indukcyjnej na działanie rozszerzonego obserwatora prędkości
PublikacjaW artykule opisano metodę odtwarzania prędkości wirnika maszyny indukcyjnej przy wykorzystaniu rozszerzonego obserwatora prędkości. Zbadano wpływ błędów parametrów modelu maszyny indukcyjnej na właściwości dynamiczne obserwatora poprzez porównanie macierzy stanu obserwatora obarczonego oraz nieobarczonego błędami parametrów. Zbadany został także wpływ błędów parametrów na jakość odtwarzania zmiennych maszyny w stanie ustalonym.
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СИСТЕМА КОНТРОЛЯ СОСТОЯНИЯ ИЗОЛЯЦИИ ЭЛЕКТРОПРИВОДОВ В СЕТЯХ С ГЛУХОЗАЗЕМЛЕННОЙ НЕЙТРАЛЬЮ (System of insulation status monitoring for electric drives in networks with a dead-earth neutral)
PublikacjaПредложен метод контроля изоляции частотно-регулируемых электроприводов в сетях с глухозаземленной нейтралью. Система контроля изоляции включается в момент остановки электропривода. Ключи инвертора коммутируются по специальному закону, и с помощью сигнала трансформатора тока, который изме- ряет ток во всех трех фазах привода одновременно, определяется ток утечки. Рассмотрена схема датчика тока утечки и приведены экспериментальные...
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Modeling the impact of discretizing rotor angular position on computation of field-oriented current components in high speed electric drives
PublikacjaModern drives consist of alternating current electric motors, and the field-oriented control (FOC) of such motors enables fast, precise, and robust regulation of a drive's mechanical variables such as torque, speed, and position. The control algorithm, implemented in a microprocessor, requires feedback from motor currents, and the quality of this feedback is essential to a drive's control properties. Motor phase currents are sampled...
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Broken rotor symptoms in the sensorless control of induction machine
PublikacjaThe purpose of this paper is to investigate the need for a universal method for sensorless controlled induction motor drive diagnosis. The increasing number of sensorless control systems in industrial applications require a universal method for the drive diagnosis, which provides reliable diagnostic reasoning independent of control system structure and state variables measurement or estimation method.Simulations and experimental...
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Nilpotent singularities and chaos: Tritrophic food chains
PublikacjaLocal bifurcation theory is used to prove the existence of chaotic dynamics in two well-known models of tritrophic food chains. To the best of our knowledge, the simplest technique to guarantee the emergence of strange attractors in a given family of vector fields consists of finding a 3-dimensional nilpotent singularity of codimension 3 and verifying some generic algebraic conditions. We provide the essential background regarding...
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Topological-numerical analysis of a two-dimensional discrete neuron model
PublikacjaWe conduct computer-assisted analysis of a two-dimensional model of a neuron introduced by Chialvo in 1995 [Chaos, Solitons Fractals 5, 461–479]. We apply the method of rigorous analysis of global dynamics based on a set-oriented topological approach, introduced by Arai et al. in 2009 [SIAM J. Appl. Dyn. Syst. 8, 757–789] and improved and expanded afterward. Additionally, we introduce a new algorithm to analyze the return times...
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Human subarachnoid space width oscillations in the resting state
PublikacjaAbnormal cerebrospinal fluid (CSF) pulsatility has been implicated in patients suffering from various diseases, including multiple sclerosis and hypertension. CSF pulsatility results in subarachnoid space (SAS) width changes, which can be measured with near-infrared transillumination backscattering sounding (NIR-T/BSS). The aim of this study was to combine NIR-T/BSS and wavelet analysis methods to characterise the dynamics of the...
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A NOVEL CONCEPT OF H2/O2 STEAM GENERATOR
PublikacjaThis paper presents an idea of hydrogen utilization to steam generation to drive a turbine and produce electricity or to supply a condenser as an element of heating system. Electrolysis process is considered as a source of hydrogen as well as oxygen. Hydrogen combustion with a stoichiometric ratio of pure oxygen produces steam at very high temperature. Steam temperature can be controlled by mixing the generated steam with liquid...
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Numerical investigations of the engine cooling system in a small power vesel pod propulsion system
PublikacjaThe development of electronics and electrotechnology enabled to put electric motors of the alternating current in the pod and to use them for the main drive of ships. A lot of heat which must be picked up from the system is a problem which is turning up at applying the system of this type. Many big ships lately contended with these problems. Building the small propeller for the boat powered with solar power we decided to check...
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Control of induction machine supplied by a current source inverter using the multi-scalar transformation and backstepping approach
PublikacjaThe paper describes the voltage control technique of squire-cage induction machines supplied by a current source inverter. The control system is based on new transformation of the electric drive system (machine and inverter) state variables to the multi-scalar variables form. The backstepping approach is used to obtain the feedback control law. The control system contains the structure of the observer...
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A novel concept of H2/O2 steam generator
PublikacjaThis paper presents an idea of hydrogen utilization to steam generation to drive a turbine and produce electricity or to supply a condenser as an element of a heating system. Electrolysis process is considered as a source of hydrogen as well as oxygen. Hydrogen combustion with a stoichiometric ratio of pure oxygen produces steam at very high temperature. Steam temperature can be controlled by mixing the generated steam with liquid...