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Wyświetlanie 1-15 z 46
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:
Steady-state modelling method for matrix-reactance frequency converter with boost topology
Autorzy:
Korotyeyev, I.Ye.
Zięba, B.
Powiązania:
https://bibliotekanauki.pl/articles/140872.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
przekształtnik AC/AC
matrycowo-reaktancyjny przemiennik częstotliwości
metoda Galerkina
równanie różniczkowe
AC/AC converters
matrix-reactance frequency converter
Galerkin's method
extension of differential equations
Opis:
This paper presents a method intended for calculation of steady-state processes in AC/AC three-phase converters that are described by nonstationary periodical differential equations. The method is based on the extension of nonstationary differential equations and the use of Galerkin's method. The results of calculations are presented in the form of a double Fourier series. As an example, a three-phase matrix-reactance frequency converter (MRFC) with boost topology is considered and the results of computation are compared with a numerical method.
Źródło:
Archives of Electrical Engineering; 2011, 60, 2; 137-148
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power flow controller based on bipolar direct PWM AC/AC converter operation with active load
Autorzy:
Kaniewski, Jacek Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/141487.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power flow controller
direct AC/AC converter
matrix chopper
power quality
Opis:
The uncontrolled power flow in the AC power system caused by renewable energy sources (restless sources, distributed energy sources), dynamic loads, etc., is one of many causes of voltage perturbation, along with others, such as switching effects, faults, and adverse weather conditions. This paper presents a three-phase voltage and power flow controller, based on direct PWM AC/AC converters. The proposed solution is intended to protect sensitive loads against voltage fluctuation and problems with power flow control in an AC power system. In comparison to other solutions, such as DVR, UPFC, the presented solution is based on bipolar matrix choppers and operates without a DC energy storage unit or DC link. The proposed solution is able to compensate 50% voltage sags, in the case of three-phase symmetrical voltage perturbation, and single phase voltage interruptions. Additionally, by means of a voltage phase control with a range of 60◦ in each phase, it is possible to control the power flow in an AC power system. The paper presents an operational description, a theoretical analysis based on the averaged state space method and four terminal descriptions, and the experimental test results from a 1 kVA laboratory model operating under active load.
Źródło:
Archives of Electrical Engineering; 2019, 68, 2; 341-356
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
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:
Application of the matrix converter to power flow control
Autorzy:
Szcześniak, P.
Fedyczak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/141546.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
matrix converter
AC systems
power flow
Opis:
Advanced power electronic converters can provide the means to control power flow and ensure proper and secure operation of the future power grid. The small electrical energy sources dispersed in electrical power systems referred to as distributed generation are one of the most significant parts of future grids - Smart Grids. The threephase, direct matrix converter is an alternative solution to the conventional AC-DC-AC converter for interfacing two AC systems in distributed power generation with different voltage and/or frequency parameters. This paper presents a control analysis of a threephase matrix converter employed as a power interface of future electrical grids. The proposed system has been successfully tested for bidirectional power flow operation with different grid operating conditions, such as, frequency and voltage variation.
Źródło:
Archives of Electrical Engineering; 2014, 63, 3; 409-422
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
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:
A coefficient diagram method based AGC mechanism for an interconnected power system in coordination with UPFC and AC/DC link
Autorzy:
Sahani, A.K.
Shankaro, Ravi
Sariki, Murali
Mandal, Rajib Kumar
Powiązania:
https://bibliotekanauki.pl/articles/140700.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AGC
AC/DC link
CDM
GDB
GRC
UPFC
Opis:
Frequency regulation is in a first line of preference for an interconnected power system. Presence of nonlinearities in the generation systems further raises the complexity level of the problem. In this scenario, this article presents a robust Automatic Generation Control (AGC) mechanism to maintain the frequency and tie-line power of the power system to their nominal values. A Coefficient Diagram Method (CDM) based AGC mechanism including an AC/DC tie-line and Unified Power Flow Controller (UPFC) has been developed and the performance in handling the frequency regulation has been analyzed. The nonlinearities such as Governor Dead-Band (GDB) and Generation Rate Constraint (GRC) are included in the system to analyze the proposed AGC scheme in a more realistic approach. The AC/DC tie-line and UPFC which are included in the proposed AGC scheme provides an immense strength to handle the active power variation as-well-as frequency regulation. To develop a more effective AGC scheme, the parameters of an AC/DC tie-line and UPFC are optimized by successful implementation of the Fruit Fly Optimization Algorithm (FOA). The justification of the proposed AGC scheme has been carried out through a step by step verification such as justifying the CDM based controller, effectiveness of the proposed scheme and robustness of the system against parameters variation. The CDM based controller has been compared with the conventional controllers to elevate the effectiveness and the supremacy of the proposed AGC scheme has been examined by comparing with previously published work. The design and simulation of the work has been carried out by the MATLAB/Simulink® tool box.
Źródło:
Archives of Electrical Engineering; 2020, 69, 2; 287-302
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
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:
A modelling of AC voltage stabilizer based on a hybrid transformer with matrix converter
Autorzy:
Szcześniak, P.
Powiązania:
https://bibliotekanauki.pl/articles/140776.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC voltage stabilizer
averaged model
hybrid transformer
matrix converter
Opis:
This article presents a study of an AC voltage stabilizer based on a three-phase hybrid transformer combined with a matrix converter. The proposed solution is used to control AC voltage amplitude and phase shift. By adjustment of these voltage parameters we can reduce the effects of overvoltage, voltage dips or lamp flicker. Such negative phenomena are very significant, particularly from the perspective of the final consumer and sensitive loads connected to the power network. Often the voltage in the power system can be adjusted using a mechanical or thyristor controlled regulator, which in a stepwise manner switches the taps of the electromagnetic transformer. The method for obtaining continuous control of the voltage magnitude and phase shift with the use of a conventional transformer with two output windings and a matrix converter is presented in this paper. The operating principles, mathematical model and properties of the proposed voltage stabilizers are discussed in this paper. The main part of the article will be devoted to the mathematical model which is based on an averaged equation. Computer simulation results are presented and compared with the results of a mathematical study.
Źródło:
Archives of Electrical Engineering; 2017, 66, 2; 371-382
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling and reliability analysis of three phase z-source AC-AC converter
Autorzy:
Prasad, H.
Maity, T.
Powiązania:
https://bibliotekanauki.pl/articles/140661.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
real-time digital simulation (RTDS)
field programming gate array (FPGA)
hardware-in-the-loop (HIL)
z-source ac-ac converter
PID controller
Opis:
This paper presents the small signal modeling using the state space averaging technique and reliability analysis of a three-phase z-source ac-ac converter. By controlling the shoot-through duty ratio, it can operate in buck-boost mode and maintain desired output voltage during voltage sag and surge condition. It has faster dynamic response and higher efficiency as compared to the traditional voltage regulator. Small signal analysis derives different control transfer functions and this leads to design a suitable controller for a closed loop system during supply voltage variation. The closed loop system of the converter with a PID controller eliminates the transients in output voltage and provides steady state regulated output. The proposed model designed in the RT-LAB and executed in a field programming gate array (FPGA)-based real-time digital simulator at a fixedtime step of 10 μs and a constant switching frequency of 10 kHz. The simulator was developed using very high speed integrated circuit hardware description language (VHDL), making it versatile and moveable. Hardware-in-the-loop (HIL) simulation results are presented to justify the MATLAB simulation results during supply voltage variation of the three phase z-source ac-ac converter. The reliability analysis has been applied to the converter to find out the failure rate of its different components.
Źródło:
Archives of Electrical Engineering; 2017, 66, 4; 731-743
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The model of double-cage induction motor for the analysis of thermal fields in transient operations
Autorzy:
Mróz, J.
Powiązania:
https://bibliotekanauki.pl/articles/141544.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC motors
heating
induction motors
squirrel cage motors
temperature rise
Opis:
Emergency motor switch-on happens occasionally while operating a doublesquirrel- cage motor at full supply voltage with the rotor blocked (e.g., in coal mills). After releasing the blockage, the by now heated motor is started up again. However, the mechanical stress caused by the increased temperature poses considerable hazards to the squirrel-cage winding. This paper presents a double-cage induction motor model for analysis of thermal fields in transient operation. The thermal field for the rotor of a doublesquirrel- cage motor of soldered or cast structure, operating in the conditions described, has been calculated in the present paper using a thermal network method. Measurement results have been presented for the double-squirrel-cage winding temperature for a soldered cage construction in the blocked rotor state.
Źródło:
Archives of Electrical Engineering; 2017, 66, 2; 397-408
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production and properties of composite material comprising Gd multiscale particles
Autorzy:
Jaworski, J.
Gawłowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/407095.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gadolinium
producing
Gd particles
multiscale particles
paraffin
AC electric discharge
Opis:
The article presents a novel method of producing Gd particles and preserving them from oxidation. The particles were produced in liquid paraffin by means of AC electric discharge and stored in the solidified paraffin. After seven months, the surface of the Gd was found to be exempt of oxidation. Moreover a composite material formed from mixing paraffin with Gd particles was conductive and magnetic and also presented photovoltaic effect. This method is a promising means of producing, at an industrial scale, particles from materials extremely sensitive to environment such as rare earth materials. Also the new material consisted of Gd particles in a paraffin matrix can find applications in many branches of industry.
Źródło:
Management and Production Engineering Review; 2015, 6, 1; 16-20
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 46

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