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    Wyświetlanie 1-13 z 13
    Tytuł:
    Simple three-level neutral point voltage balance control strategy based on SVPWM
    Autorzy:
    Bo, G.
    Shanmei, Ch.
    Yi, Q.
    Powiązania:
    https://bibliotekanauki.pl/articles/141238.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    space vector
    neutral point voltage
    voltage offset
    PWM
    Opis:
    The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC) inverter, the effect of neutral point voltage balancing which is caused by voltage vector is analyzed, and the relationship of the voltage offset and neutral point voltage is studied in this paper. This paper proposes a novel neutral point balance strategy for three-level NPC inverter based on space vector pulse width modulation (SVPWM). A voltage offset is added to the modulation wave, and a closed-loop neutral point voltage balance control system is designed. In the control system, the dwelling time of synthesis voltage vectors for SVPWM is varied to solve the problem of the unbalance of the neutral point voltage, the sequence of the voltage vectors maintains unchanging. Simulation and experimental results show the neutral point voltage balancing control strategy based on SVPWM is effective.
    Źródło:
    Archives of Electrical Engineering; 2013, 62, 1; 15-23
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study by modeling and simulation of open-switch fault diagnosis for five-level converters
    Autorzy:
    Becker, F.
    Jamshidpour, E.
    Poure, P.
    Saadate, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/136241.pdf
    Data publikacji:
    2017
    Wydawca:
    EEEIC International Barbara Leonowicz Szabłowska
    Tematy:
    open switch fault
    fault diagnosis
    fault detection
    fault localization
    Multilevel converter
    neutral point
    H-bridge
    Opis:
    In this paper, an open-switch fault diagnosis method for five-level H-Bridge Neutral Point Piloted (HB-NPP) or T-type converters is proposed. While fault tolerant operation is based on three steps (fault detection, fault localization and system reconfiguration), a fast fault diagnosis, including both fault detection and localization, is mandatory to make a suitable response to an open-circuit fault in one of the switches of the converter. Furthermore, fault diagnosis is necessary in embedded and safety critical applications, to prevent further damage and perform continuity of service. In this paper, we present an open-switch fault diagnosis method, based on the switches control orders and the observation of the converter output voltage level. In five-level converters such as HB-NPP and T-type topologies, some switches are mostly 'on' at the same time. Therefore, the fault localization is quite complicated. The fault diagnosis method we proposed is capable to detect and localize an open-switch fault in all cases. Computer simulations are carried out by using Matlab Simulink and SimPowerSystem toolbox to validate the proposed approach.
    Źródło:
    Transactions on Environment and Electrical Engineering; 2017, 2, 1; 27-34
    2450-5730
    Pojawia się w:
    Transactions on Environment and Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Grid-Tied Neutral Point Clamped based Centralised Photovoltaic Inverter with Improved DC Link Voltage Balancing and Harmonic Minimisation Control
    Autorzy:
    Bhowmick, Supratik
    Mukherjee, Debranjan
    Maiti, Suman
    Chakraborty, Chandan
    Powiązania:
    https://bibliotekanauki.pl/articles/1955983.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    photovoltaic multilevel inverter
    neutral point voltage balancing
    space vector pulse width modulation
    current harmonic minimisation
    Opis:
    This paper proposes an improved space vector pulse width modulation (SVPWM) based DC link voltage balancing control of a three-phase three-level neutral point clamped (NPC) centralised inverter supplying the generated power from photo voltaic (PV) array to a three-phase utility grid. Two possible schemes have been developed based on the power conversion stage between PV array and the utility grid namely, two-stage (three-level boost converter three-phase three-level NPC inverter) and single-stage (three-phase three-level NPC inverter alone). The comparison between these two schemes has been thoroughly discussed in terms of the control strategies employed, power loss analysis and efficiency. The performance of the centralised inverter under different modes of operation has been investigated by developing the required control strategies for smooth operation. Using the proposed control strategy, the centralised inverter can be operated as a static synchronous compensator (STATCOM) during night time, if needed. The power loss incurred in the power-electronic converters has been analysed for constant and also for variable ambient temperature. The effectiveness of the centralised inverter as an active filter (AF) has also been verified when a three-phase non-linear load is considered in the system.
    Źródło:
    Power Electronics and Drives; 2021, 6, 41; 185-203
    2451-0262
    2543-4292
    Pojawia się w:
    Power Electronics and Drives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Model predictive control of NPC three-level grid-tied converter based on reconstructed current
    Autorzy:
    Li, Yanyan
    Xiao, Han
    Jin, Nan
    Yan, Guanglu
    Powiązania:
    https://bibliotekanauki.pl/articles/2086686.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    current reconstruction
    current sensor fault
    fault-tolerant
    model predictive control
    neutral point clamped three-level converter
    Opis:
    The neutral point clamped (NPC) three-level grid-tied converter is the key equipment connecting renewable energy and power grids. The current sensor fault caused by harsh environment may lead to the split of renewable energy. The existing sensor fault-tolerant methods will reduce the modulation ratio index of the converter system. To ensure continuous operation of the converter system and improve the modulation index, a model predictive control method based on reconstructed current is proposed in this paper. According to the relationship between fault phase current and a voltage vector, the original voltage vector is combined and classified. To maintain the stable operation of the converter and improve the utilization rate of DC voltage, two kinds of fault phase current are reconstructed with DC current, normal phase current and predicted current, respectively. Based on reconstructed three-phase current, a current predictive control model is designed, and a model predictive control method is proposed. The proposed method selects the optimal voltage vector with the cost function and reduces time delay with the current reconstruction sector. The simulation and experimental results show that the proposed strategy can keep the NPC converter running stably with one AC sensor, and the modulation index is increased from 57.7% to 100%.
    Źródło:
    Archives of Electrical Engineering; 2022, 71, 2; 363--377
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A state-space approach for control of NPC type 3-level sine wave inverter used in FOC PMSM drive
    Autorzy:
    Tarczewski, T.
    Grzesiak, L. M.
    Wawrzak, A.
    Karwowski, K.
    Erwiński, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/200731.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    state feedback control
    linear quadratic regulator
    3-level neutral point clamped voltage source inverter
    LC filter
    Opis:
    This paper presents the design and analysis process of state feedback controllers for NPC type 3-level sine wave inverter. In order to achieve good dynamic features in a state feedback control an internal model of reference input and a feedforward path are introduced. During synthesis process of the state feedback controllers maximum permissible dynamics of voltage control in the linear range of modulation is taken into account. It is shown that initially gains of the controller and feedforward path are non-stationary and depend on the angular velocity. Stationary approximation of a non-stationary state feedback controller is presented in details. Proposed state feedback control structures for continuous voltage shaping NPC type 3-level voltage source inverter are examined in FOC PMSM drive. The novelty of the presented controller lays in a stationary approximated state feedback control structure designed in terms of maximum permissible dynamics of a voltage control system. Simulation and experimental results (at the level of 3 kW) of the designed control algorithms are included.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 3; 439-448
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stability by Krasnoselskiis theorem in totally nonlinear neutral differential equations
    Autorzy:
    Derrardjia, I.
    Ardjouni, A.
    Djoudi, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1397510.pdf
    Data publikacji:
    2013
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    fixed point
    stability
    nonlinear neutral equation
    Krasnoselskii-Burton theorem
    Opis:
    In this paper we use fixed point methods to prove asymptotic stability results of the zero solution of a class of totally nonlinear neutral differential equations with functional delay. The study concerns $x^\prime (t)= -a(t)x^3(t) + c(t)x^\prime (t-r(t)) + b(t) x^3 (t-r(t)) $. The equation has proved very challenging in the theory of Liapunov’s direct method. The stability results are obtained by means of Krasnoselskii-Burton’s theorem and they improve on the work of T.A. Burton (see Theorem 4 in [Liapunov functionals, fixed points, and stability by Krasnoselskii’s theorem, Nonlinear Studies 9 (2001), 181–190]) in which he takes c=0 in the above equation
    Źródło:
    Opuscula Mathematica; 2013, 33, 2; 255-272
    1232-9274
    2300-6919
    Pojawia się w:
    Opuscula Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Existence of periodic solutions for totally nonlinear neutral differential equations with functional delay
    Autorzy:
    Yankson, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/254907.pdf
    Data publikacji:
    2012
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    fixed point
    large contraction
    periodic solution
    totally nonlinear neutral equation
    Źródło:
    Opuscula Mathematica; 2012, 32, 3; 617-627
    1232-9274
    2300-6919
    Pojawia się w:
    Opuscula Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Deflection of Steel Reinforced Concrete Beam Prestressed with CFRP Bar
    Autorzy:
    Selvachandran, P.
    Anandakumar, S.
    Muthuramu, K. L.
    Powiązania:
    https://bibliotekanauki.pl/articles/353032.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cracked moment of inertia
    deformability
    effective moment of inertia
    neutral axis
    Partial Prestressig Ratio
    yielding point
    Opis:
    Carbon Fiber Reinforced polymer (CFRP) bars are weak in yielding property which results in sudden failure of structure at failure load. Inclusion of non-pretensioned steel reinforcement in the tension side of CFRP based prestressed concrete beam will balance the yielding requirements of member and it will show the definite crack failure pattern before failure. Experimental investigation has been carried out to study the deflection behavior of partially prestressed beam. Experimental works includes four beam specimens stressed by varying degree of prestressing. The Partial Prestressing Ratio (PPR) of specimen is considered for experimental works in the range of 0.6 to 0.8. A new deflection model is recommended in the present study considering the strain contribution of CFRP bar and steel reinforcement for the fully bonded member. New deflection model converges to experimental results with the error of less than 5% .
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 3; 1915-1922
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lossless transmission lines terminated by crystal oscillator circuit
    Autorzy:
    Angelov, Vasil G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1065397.pdf
    Data publikacji:
    2019
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Fixed point theorem
    Kirchhoff’s law
    Lossless transmission line
    Mixed problem for hyperbolic system
    Neutral equation
    Periodic solution
    Opis:
    The present paper deals with ТЕМ propagation of waves along lossless transmission lines terminated by a crystal oscillator circuit. The crystal oscillator circuit generates nonlinear boundary conditions derived by the Kirchhoff’s law. Then the mixed problem for the hyperbolic transmission line system to an initial value problem for neutral system on the boundary is reduced. The main purpose of the present paper is to show an existence-uniqueness of a periodic solution of the neutral system. This is achieved by introducing a suitable operator acting on a space of periodic functions. Its fixed point is a periodic solution of the neutral system. The advantages of the presented method on numerical example are demonstrated. The solution can be obtained by successive approximations.
    Źródło:
    World Scientific News; 2019, 132; 65-83
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On some topological methods in theory of neutral type operator differential inclusions with applications to control systems
    Autorzy:
    Kamenskii, Mikhail
    Obukhovskii, Valeri
    Yao, Jen-Chih
    Powiązania:
    https://bibliotekanauki.pl/articles/729536.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    operator differential inclusion
    neutral type
    periodic solution
    fixed point
    multivalued map
    condensing map
    topological degree
    averaging method
    control system
    distributed control
    Opis:
    We consider a neutral type operator differential inclusion and apply the topological degree theory for condensing multivalued maps to justify the question of existence of its periodic solution. By using the averaging method, we apply the abstract result to an inclusion with a small parameter. As example, we consider a delay control system with the distributed control.
    Źródło:
    Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2013, 33, 2; 193-204
    1509-9407
    Pojawia się w:
    Discussiones Mathematicae, Differential Inclusions, Control and Optimization
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Surveys of creep-susceptible locations using the method of fixed points in jointless rail track
    Pomiary miejsc podatnych na pełzanie przy zastosowaniu metody punktów stałych w torze bezstykowym
    Autorzy:
    Strach, M.
    Kampczyk, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/386076.pdf
    Data publikacji:
    2010
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    tor bezstykowy
    temperatura neutralna
    punkt stały
    punkt bazowy
    mikroprzemieszczenia szyn
    pełzanie szyn
    przemieszanie toru
    jointless rail track
    neutral temperature
    fixed point
    base point
    rail micro-shifts
    rail creep
    track shift
    Opis:
    The article deals with the problems as well as principles of conducting surveys and observations of creep-susceptible locations of rail courses in a jointless rail track using the method of fixed points. The paper presents and discusses the results of authors’ surveys of rail courses creep of the No. 1 jointless rail track of the railway line No. 161 Katowice-Szopienice Północne – Chorzów Stary, which were carried out in the spring of 2008 and 2009. The total length of the jointless rail track covered by the monitoring was 5.227 km. The distribution velocity at this section equaled to 80 km/h. In addition, photographs and own observations on the relevant issues were presented. Due to the limitations in size, the article sets out the most important aspects of conducting surveying works, which are to determine the occurring shifts as well as to mark the fixed points and reference points. It also presents the manner of carrying out the analysis and final assessment of the jointless rail track operation.
    Artykuł opisuje problematykę i zasady prowadzenia pomiarów i obserwacji miejsc podatnych na pełzanie toków szynowych w torze bezstykowym przy zastosowaniu metody punktów stałych. W pracy przedstawiono i omówiono wyniki pomiarów autorskich pełzania toków szynowych toru bezstykowego nr 1 linii kolejowej nr 161 Katowice-Szopienice Północne – Chorzów Stary, które przeprowadzono wiosną 2008 i 2009 roku. Całkowita długość toru bezstykowego objętego monitoringiem wynosi 5,227 km. Prędkość rozkładowa na tym odcinku wynosi 80 km/h. Dodatkowo zaprezentowane zostały fotografie i własne spostrzeżenia dotyczące opisywanych zagadnień. Z uwagi na ograniczoną objętość artykułu ujęto w nim jedynie najważniejsze aspekty zarówno prowadzenia prac pomiarowych w celu określenia występujących przemieszczeń, jak i prowadzenia oznaczeń punktów stałych i punktów bazowych. Przedstawiono również sposób wykonywania analizy i ostatecznej oceny pracy toru bezstykowego.
    Źródło:
    Geomatics and Environmental Engineering; 2010, 4, 1/1; 125-136
    1898-1135
    Pojawia się w:
    Geomatics and Environmental Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On Nonlinear Fractional Neutral Differential Equation with the ψ-Caputo Fractional Derivative
    Autorzy:
    Nabil, Tamer
    Powiązania:
    https://bibliotekanauki.pl/articles/1818657.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
    Tematy:
    Krasnoselskii's fixed point theory
    ψ − Caputo operator
    neutral differential equation
    ulam stability
    existence of solution
    teoria punktu stałego Krasnoselskiego
    operator Caputa
    równanie różniczkowe
    stabilność Ulama
    Opis:
    In this article, the solvability of fractional neutral differential equation involving ψ−Caputo fractional operator is considered usinga Krasnoselskii’s fixed point approach. Also, we establish the uniquenessof the solution under certain conditions. Ulam stabilities for the proposedproblem are discussed. Finally, examples are displayed to aid the applicability of the theory results.
    Źródło:
    Journal of Mathematics and Applications; 2020, 43; 99--112
    1733-6775
    2300-9926
    Pojawia się w:
    Journal of Mathematics and Applications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Measure of noncompactness and neutral functional differential equations with state-dependent delay
    Autorzy:
    Benchohra, M.
    Henderson, J.
    Medjadj, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/357717.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
    Tematy:
    neutral functional differential equation
    mild solution
    infinite delay
    state-dependent delay
    fixed point
    semigroup theory
    cosine function
    measure of noncompactness
    równanie różniczkowe
    zagadnienie Cauchy'ego
    opóźnienia nieskończone
    punkt stały
    teoria półgrup
    funkcja cosinus
    miara niezwartości
    Opis:
    Our aim in this work is to study the existence of solutions of first and second order for neutral functional differential equations with state-dependent delay. We use the Mönch’s fixed point theorem for the existence of solutions and the concept of measures of noncompactness.
    Źródło:
    Journal of Mathematics and Applications; 2016, 39; 23-45
    1733-6775
    2300-9926
    Pojawia się w:
    Journal of Mathematics and Applications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

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