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Wyświetlanie 1-15 z 19
Tytuł:
Efficiency improvement due to direct torque and flux three levels three areas control method applied to small hydroelectric power plant
Autorzy:
Kulikowski, K.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/200033.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
asynchronous machine
AC/DC/AC converter
DC/AC converter
DTC
flux control
Opis:
The paper presents a description of a new DTFC3L3A (direct torque and flux control three levels three areas) control method of induction machine as well as its comparison with the DTC method. The basis for the comparison is the switching frequency of described methods. The proposed method is optimized to reduce number of switchings (which is proportional to switching power losses) in static state, as well as it takes into account the angle which makes it possible to obtain a sinusoidal shape of flux within range of low angular frequencies of an asynchronous machine. The paper includes the results of experiments performed on a three level DC/AC inverter for both control methods.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 569-574
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AC/DC/AC converter in a small hydroelectric power plant
Autorzy:
Sikorski, A.
Korzeniowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200049.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
induction generator
AC/DC/AC converter
hydroelectric power plant
Opis:
The article discusses application of AC/DC/AC converter cooperating with an induction generator in small hydroelectric power plants. The induction generator works with power grid or a separated group of receivers, enabling to generate power even at low speeds of the turbine. The article provides also results of the investigation concerning the functioning of the generator coupled with AC/DC/AC converter in steady and transient states during start-up and voltage decay.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 507-511
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predictive and look-up table control methods of a three-level AC-DC converter under distorted grid voltage
Autorzy:
Falkowski, P.
Kulikowski, K.
Grodzki, R.
Powiązania:
https://bibliotekanauki.pl/articles/201956.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
three-level AC/DC converter
direct power control
finite contol set model predictive control
lookup table method
AC/DC
trzypoziomowy konwerter AC/DC
Opis:
Power electronic three-level AC-DC converters connecting a utility grid with DC supplies are widely used in renewable energy sources. For such distributed systems, the quality of energy is very important. Hence, control algorithms of an AC-DC converter have to provide not only a sinusoidal shape of grid current, but also stable operation during transient states in the grid, e.g. voltage dips or voltage unbalance. This paper deals with the problem of robustness of AC-DC control methods under disturbed grid voltage. Three modern predictive control algorithms are presented and investigated under grid voltage distortions. Experimental results from a laboratory test setup illustrating properties of the described methods are shown.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 5; 609-618
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modern Direct Torque and Flux Control methods of an induction machine supplied by three-level inverter
Autorzy:
Sikorski, A.
Kulikowski, K.
Korzeniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/201199.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
asynchronous machine
DC/AC inverter
DTC
flux and torque control
3-level DC/AC inverter
Opis:
This paper describes two modern direct torque and flux control methods of an induction machine supplied by a three-level inverter. Additionally, it presents a comparison of the methods both in static and dynamic states. The methods, in a specific way, make use of an increased number of active vectors of the three-level inverter in order to improve control quality and reduce switching frequency. The two methods modify the DTC method by using its advantages and eliminating, at the same time its drawbacks. In static states the comparison was based on the results of investigations performed for two different load values and three set values of angular speed, whereas in dynamic states the comparison was focused on the behavior of the machine at startup. The results of the investigations have shown that both methods give very good performance. They are characterized by both sinusoidal shape of flux and low current deformations even at low angular speeds i.e. less than 10% of the nominal value. The presented methods also allow to generate nominal flux for set zero angular speed in order to achieve excitation of the induction machine. The switching frequencies for both methods are very similar in almost the whole range of control but the methods have shown some differences in control quality, particularly for higher torque values.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 4; 771-778
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of space vector modulation algorithm on characteristics of three-phase voltage inverter for drives of optical telescopes
Autorzy:
Tomasov, V.
Usoltsev, A.
Zolov, P.
Gribanov, P.
Powiązania:
https://bibliotekanauki.pl/articles/200303.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multilevel inverter
space vector modulation
modulation algorithm
current ripple
precision AC drive
inwerter
modulacja
napęd AC
Opis:
The effect of space vector modulation algorithm on magnitude of current vector ripples was considered on the mathematical model of a three-level three-phase voltage inverter with symmetric active inductive load. Limitations on the use of such inverters as a power supply for precision drive of optical telescopes were specified.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 5; 629-637
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System efficiency for AC vs. DC distribution paradigms: a comparative evaluation
Autorzy:
Gelani, Hasan Erteza
Khan, Sidra
Dastgeer, Faizan
Idrees, Zeba
Afzal, Muhammad Waqas
Nasir, Mashood
Powiązania:
https://bibliotekanauki.pl/articles/2173534.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC vs DC
DC distribution
efficiency analysis
residential loads
AC/DC
dystrybucja prądu stałego
analiza wydajności
obciążenie mieszkalne
Opis:
The birth of electricity witnessed “the battle of currents” between AC and DC as a medium of power transfer. AC won the battle in the first place because of its ability to transform voltage levels. However, with the development of power electronic converters (PECs), DC is striking back. Most of the electronic loads in our conventional AC-based homes are DC by nature. Moreover, the modern concept of energy-efficient variable speed drive (VSD) based loads, i.e. DC-inverter based air-conditioners and refrigerators, require a DC link for their operation. The driving component of all such loads is the PEC. The operational efficiency of PECs depends on the loading which varies throughout the day. This paper presents a mathematical model based on a bottom-up approach to the comparative efficiency analysis of AC and DC distribution systems considering daily load variation. Two topologies are presented where AC and DC distribution systems are compared in terms of efficiency. The first topology (T1) defines a separate/independent converter for each load, whereas in the second topology (T2) loads of a particular class are lumped and driven by a single converter. The results present DC distribution better than AC distribution with an efficiency advantage of 2.28% and 1.57% for T1 and T2, respectively.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 1; e139956, 1--9
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dedicated system for design, analysis and optimization of AC-DC converters
Autorzy:
Piasecki, S.
Szmurlo, R.
Rabkowski, J.
Jasiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/201404.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC-DC converter
multi-objective optimization
design methodology
distributed generation systems
konwerter AC-DC
optymalizacja wielokryterialna
metodologia projektowania
generacja rozproszona
Opis:
This paper presents an originally-developed system for design and optimization of AC-DC converters dedicated in particular to operation in distributed generation systems. The proposed procedure is based on a multi-objective discrete optimization and expert knowledge of electrical engineering, especially power electronics. The required accuracy of calculations is obtained by using the database with real components, while the parameters applied in calculations are based on parameters provided by the manufacturer. The paper presents the foundations and basic system properties, the design and optimization process, and selected optimization results, obtained with a fully functional prototype of the design and optimization system (DaOS).
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 4; 897-905
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and construction of a polygon-connected autotransformer-based 36-pulse AC-DC converter for power quality improvement in retrofit applications
Autorzy:
Abdollahi, R.
Powiązania:
https://bibliotekanauki.pl/articles/202052.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC-DC converter
polygon autotransformer
power quality
36-pulse rectifier
direct torque controlled induction motor drive (DTCIMD)
konwerter AC-DC
jakość energii
prostownik impulsowy
DTCIMD
Opis:
This paper presents the design and analysis of a polygon connected autotransformer based 36-phase AC-DC converter which supplies direct torque controlled induction motor drives (DTCIMD’s) in order to have better power quality conditions at the point of common coupling. The proposed converter output voltage is accomplished via two paralleled eighteen-pulse AC-DC converters each of them consisting of nine-phase diode bridge rectifier. An autotransformer is designed to supply the rectifier. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. The proposed structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 4% for the proposed topology at variable loads. A laboratory prototype of the proposed Polygon-Connected autotransformer-based 36-pulse AC-DC converter is developed and test results are presented to validate the developed design procedure and the simulation models of this AC-DC converter under varying loads.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 2; 353-362
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analyses of residential building efficiency for AC and DC distribution networks
Autorzy:
Ahmad, Faraz
Dastgeer, Faizan
Gelani, Hasan E.
Khan, Sidra
Nasir, Mashood
Powiązania:
https://bibliotekanauki.pl/articles/2128137.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DC distribution system
efficiency analysis
AC vs DC
residential buildings
solar PV
system dystrybucji prądu stałego
analiza wydajności
prąd zmienny
prąd stały
AC/DC
budynki mieszkalne
fotowoltaika
Opis:
The escalating prevalence of rooftop solar PVs and DC powered home appliances are the driving forces for the research in the field of DC distribution at residential level. The current research work presents comparative analyses of AC and DC distribution systems considering various scenarios for the specific purpose of efficiency/energy savings. A modern Bakersfield CA, USA home is considered for the analyses. The loads are classified according to the power demand. Rooftop solar PVs are also included in each residential building. Mathematical equations are devised for the efficiency analysis of residential buildings powered with AC as well as DC. The results reveal strong dependence of the efficiency values on the utilization/types of loads, efficiencies of the power electronic converters (PECs), solar capacity and seasonal conditions, as a function of the time of day. It is concluded that AC system presents better efficiency values as compared to the DC counterpart except during the time periods when solar power is available and when the penetration of variable speed drive (VSD) based loads is high.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; e136732, 1--9
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High quality repetitive control system for a grid-tied converter under distorted grid voltage conditions – design and implementation
Autorzy:
Ufnalski, Bartlomiej
Straś, Andrzej
Grzesiak, Lech M.
Powiązania:
https://bibliotekanauki.pl/articles/2173606.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC/DC power converter
current control
particle swarm optimization
power quality
repetitive control
RC
przetwornica mocy AC/DC
kontrola prądu
optymalizacja roju cząstek
jakość prądu
kontrola powtarzalna
Opis:
The paper features a grid-tied converter with a repetitive current controller. Our goal here is to demonstrate the complete design workflow for a repetitive controller, including phase lead, filtering and conditional learning. All key parameters, i.e., controller gain, filter and fractional phase lead, are designed in a single optimization procedure, which is a novel approach. The description of the design and optimization process, as well as experimental verification of the entire control system, are the most important contributions of the paper. Additionally, one more novelty in the context of power converters is verified in the physical system – a conditional learning algorithm to improve transient states to abrupt reference and disturbance changes. The resulting control system is tested experimentally in a 10 kW converter.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; art. no. e136739
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analyses of residential building efficiency for AC and DC distribution networks
Autorzy:
Ahmad, Faraz
Dastgeer, Faizan
Gelani, Hasan E.
Khan, Sidra
Nasir, Mashood
Powiązania:
https://bibliotekanauki.pl/articles/2173601.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DC distribution system
efficiency analysis
AC vs DC
residential buildings
solar PV
system dystrybucji prądu stałego
analiza wydajności
prąd zmienny
prąd stały
AC/DC
budynki mieszkalne
fotowoltaika
Opis:
The escalating prevalence of rooftop solar PVs and DC powered home appliances are the driving forces for the research in the field of DC distribution at residential level. The current research work presents comparative analyses of AC and DC distribution systems considering various scenarios for the specific purpose of efficiency/energy savings. A modern Bakersfield CA, USA home is considered for the analyses. The loads are classified according to the power demand. Rooftop solar PVs are also included in each residential building. Mathematical equations are devised for the efficiency analysis of residential buildings powered with AC as well as DC. The results reveal strong dependence of the efficiency values on the utilization/types of loads, efficiencies of the power electronic converters (PECs), solar capacity and seasonal conditions, as a function of the time of day. It is concluded that AC system presents better efficiency values as compared to the DC counterpart except during the time periods when solar power is available and when the penetration of variable speed drive (VSD) based loads is high.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; art. no. e136732
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High quality repetitive control system for a grid-tied converter under distorted grid voltage conditions – design and implementation
Autorzy:
Ufnalski, Bartlomiej
Straś, Andrzej
Grzesiak, Lech M.
Powiązania:
https://bibliotekanauki.pl/articles/2090719.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC/DC power converter
current control
particle swarm optimization
power quality
repetitive control
RC
przetwornica mocy AC/DC
kontrola prądu
optymalizacja roju cząstek
jakość prądu
kontrola powtarzalna
Opis:
The paper features a grid-tied converter with a repetitive current controller. Our goal here is to demonstrate the complete design workflow for a repetitive controller, including phase lead, filtering and conditional learning. All key parameters, i.e., controller gain, filter and fractional phase lead, are designed in a single optimization procedure, which is a novel approach. The description of the design and optimization process, as well as experimental verification of the entire control system, are the most important contributions of the paper. Additionally, one more novelty in the context of power converters is verified in the physical system – a conditional learning algorithm to improve transient states to abrupt reference and disturbance changes. The resulting control system is tested experimentally in a 10 kW converter.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; e136739, 1--11
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Grid-tied converter operated under unbalanced and distorted grid voltage conditions
Autorzy:
Gałecki, A.
Michalczuk, M.
Kaszewski, A.
Ufnalski, B.
Grzesiak, L. M.
Powiązania:
https://bibliotekanauki.pl/articles/200867.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grid tied converter
AC/DC converter
current controller
resonant controller
particle swarm optimization (PSO)
Opis:
The paper presents a three-phase grid-tied converter operated under unbalanced and distorted grid voltage conditions, using a multi-oscillatory current controller to provide high quality phase currents. The aim of this study is to introduce a systematic design of the current control loop. A distinctive feature of the proposed method is that the designer needs to define the required response and the disturbance characteristic, rather than usually unintuitive coefficients of controllers. Most common approach to tuning a state-feedback controller use linear-quadratic regulator (LQR) technique or pole-placement method. The tuning process for those methods usually comes down to guessing several parameters. For more complex systems including multi-oscillatory terms, control system tuning is unintuitive and cannot be effectively done by trial and error method. This paper proposes particle swarm optimization to find the optimal weights in a cost function for the LQR procedure. Complete settings for optimization procedure and numerical model are presented. Our goal here is to demonstrate an original design workflow. The proposed method has been verified in experimental study at a 10 kW laboratory setup.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 2; 389-398
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of supply parameters of single- and double-string LED lamps with integrated AC direct capacitorless drivers
Autorzy:
Chęciński, J.
Filus, Z.
Powiązania:
https://bibliotekanauki.pl/articles/201205.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
SSL
LED
LED-COB
PWM
power factor
efficiency
flicker
SM2082
LED AC direct driver
Opis:
Thanks to a very high luminous efficacy of LED lamps (over 160 lm/W) they are the most preferred light sources in lighting applications today. The useful lifetime of LED modules exceeds 50,000 hours. Chromatic parameters of lamps making use of SSL (Solid State Lighting) have already equalled classic solutions, although they were noticeably worse not so long ago. High values of the Colour Rendering Index and (CRI) ease of control over the luminous flux cause that lamps with LEDs have become very attractive solutions. Today, the most important problem concerns LED drivers supplied from the 230 VAC mains. The lifetime of switched-mode converters, including electrolytic capacitors, is considerably shorter than that of LEDs. This paper discusses the features of alternative drivers for LED modules which are supplied directly from the 230 VAC mains and do not contain any electrolytic capacitors. In particular, power factor and efficiency of lamps with one or two strings are analysed and some hints concerning optimal design of such lamps are given. A unique feature of this work is a detailed analysis of harmonics contents in the supply current of such drivers, proving their conformity with the relevant standard. Finally, some problems associated with flicker resulting from the considered type of supply are mentioned.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 4; 819-827
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromagnetic AC and impulse levitations of conductive, dielectric, and magnetic ball
Autorzy:
Spałek, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/2090726.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
levitation force
ball
impulse electromagnetic fields
AC electromagnetic fields
power losses
lewitacja
piłka
straty mocy
pole elektromagnetyczne impulsowe
pole elektromagnetyczne prądu przemiennego
Opis:
The paper presents an analytical solution of levitation problem for conductive, dielectric and magnetically anisotropic ball. The levitation exerts either an AC or impulse magnetic field. Both the Lorentz and material electromagnetic forces (of magnetic matter) could lift the ball in a gravitational field. The electromagnetic field distribution is derived by means of variables separation method. The total force is evaluated by Maxwell stress tensor (generalized), co-energy and Lorentz methods. Additionally, power losses are calculated by means of Joule density and the Poynting vector surface integrals. High frequency asymptotic formulas for the Lorentz force and power losses are presented. All analytical solutions derived could be useful for rapid analysis and design of levitations systems. Finally, some remarks about considered levitations are formulated.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 1; e136040, 1--9
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 19

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