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Wyświetlanie 1-15 z 232
Tytuł:
A Bidirectional Buck-Boost Converter-Based Switching Ripple Communication Strategy for Intelligent Street Lighting Systems
Autorzy:
Zhang, Yixuan
Hu, Yihua
Tse, Zion
Liu, Yuwei
Deng, Jiamei
Xu, Hui
Wang, Yangang
Li, Wei
Powiązania:
https://bibliotekanauki.pl/articles/1955998.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bidirectional switching ripple communication
buck-boost converter
intelligent street lighting system
pulse width modulation
smart city
Opis:
The light-emitting diode (LED) is an essential component of intelligent street lighting (ISL) systems. An efficient ISL system can not only reduce power consumption by planning LED illuminating time but also reduce maintenance costs through a high degree of automation. In this paper, a buck-boost converter is used to realise composite transmission of power and signals for an ISL system. The power is modulated by the pulse width modulation (PWM) approach, and the switching ripple generated in the PWM process is utilised as the carrier of the signals transmitted between the remote-control centre and the slave nodes. Moreover, the proposed model involves a ‘request to send (RTS)/confirm to send (CTS)’ mechanism to avoid signal conflicts. Compared with the conventional power line communication (PLC) approach, the proposed transmission scheme has the advantages of simple circuit structure and simple system wiring. Additionally, a simulation model built in MATLAB/Simulink proves the designed transmission method has strong anti-noise ability.
Źródło:
Power Electronics and Drives; 2021, 6, 41; 260-275
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of different modulation techniques performances in an underground multiuser communications scenario
Autorzy:
Badescu, A.-M.
Powiązania:
https://bibliotekanauki.pl/articles/106166.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
modulation techniques
commercial communication systems
CDMA
16-QAM
QPSK
Opis:
The potential use of typical commercial communication systems with ultra high frequencies for the underground emergency/military situations will be investigated, as commercial systems have already a fully developed market that makes them cheap and reliable. The possible usage of broadband techniques like CDMA in the direct sequence will be studied because most commercial communication systems have already been designed to support multiple users, as the underground propagation has many possible applications. The performances of both modulation techniques are evaluated from the point of view of the quality of the signals, power spectral density and the effect that the propagation medium has on the transmitted signals such that the best modulation technique is determined. The 16QAM and QPSK modulations (two of the most popular modulation techniques in the terrestrial wireless system) are compared in a scenario where a number of underground sources share the same physical channel (and antenna) - the receiver is placed at the ground level so the generated signals must propagate through the dielectric layer in order to reach it. The transmitted power, electric and magnetic fields as well as occupied bandwidth are also calculated.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2012, 12, 2; 73-85
1732-1360
2083-3628
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of reducing switch count in three-level NPC inverter – analysis in steady states
Autorzy:
Beniak, R.
Rogowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1193464.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reduction of switch count
three-level NPC inverter
space vector modulation
Opis:
The proof of a concept for a new method of modulation has been presented which reduce switch count in a three-level neutral point clamped (3L-NPC) inverter. The method is an implementation of space vector modulation (SVM) by means of a prediction algorithm and sequences of transistors, which are not common in use. Those sequences make active use of clamping diodes of the inverter. The prediction algorithm analyzes possible sequences of transistors’ states and choose those which offers smaller switch count. Measurements of steady states were taken on prototype 3L-NPC.
Źródło:
Power Electronics and Drives; 2017, 2, 37/2; 117-126
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of reducing switching losses in three-level NPC inverter
Autorzy:
Beniak, R.
Rogowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1193262.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reduction of switching losses
three-level NPC inverter
space vector modulation
Opis:
The aim of the paper is to present a concept of implementation of a space vector modulation (SVM) algorithm, which is used to create alternating current waveforms of changing amplitude and frequency in power inverters. The main goal of the method is to decrease the number of state changes in power transistors. It is realized by utilizing a prediction algorithm and sequences of transistors, which are not common in use. The method requires measurement of inverter output current flow. The prediction algorithm analyzes possible sequences of transistors’ states and choose those which offers smaller switch count. A decrease of about 20% was obtained for the cases tested. This paper presents simulation result for selected driving scenario. The described method decreases the number of state changes in power transistors and therefore it is a potentially good method to considerably decrease energy losses of multilevel inverter-powered drive.
Źródło:
Power Electronics and Drives; 2016, 1, 36/2; 55-63
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A model of OFDM based maritime VHF communication system for data exchange
Autorzy:
Valčić, S.
Pogány, T.
Mrak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/260386.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
maritime VHF communications
OFDM modulation
AWGN
SNR
BER
Opis:
In the maritime Very High Frequency (VHF) band, there are no systems for transmitting large amounts of data. Therefore, it is necessary to develop new systems that would modernize the Global Maritime Distress and Safety System (GMDSS), significantly relieve the Automatic Identification System’s (AIS) communication channels, and set guidelines for the development of communication infrastructure of the e-Navigation. In line with this, analytical and simulation models of the maritime VHF data transmission communication system using Orthogonal Frequency Division Multiplexing (OFDM) modulation are worked out in this paper. The achieved data rate, the spectral efficiency and the bit error rate (BER) represent validation parameters on which the results of the analytical and simulation models are evaluated. It is concluded that the application of the digital OFDM modulation in the maritime VHF band may improve the GMDSS system by achieving higher data rates compared to the current terrestrial mandatory systems for data exchange, i.e. Digital Selective Calling (DSC) and AIS.
Źródło:
Polish Maritime Research; 2018, 2; 27-36
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new closed loop speed control strategy for a vector controlled three-phase induction motor drive
Autorzy:
Tripathi, A.
Dey, A.
Dwivedi, B.
Singh, B.
Chandra, D.
Powiązania:
https://bibliotekanauki.pl/articles/262777.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
space vector modulation
VSI
induction motor model
transients
steady state value
Opis:
This paper presents a completely mathematical equations based model on control of torque and speed of a three-phase indirect vector controlled VSI fed cage induction motor drive that is controlled through the space vector modulated method. This enables a wide range of acceptability of the model for various values of load and for various types and ratings of induction motors. The uniqueness of the model lies in the fact that the deviations in the torque and speed on sudden application of reference step change in speed values are minimum i.e. when any sudden change in the speed reference is desired, the speed and torque waveforms reveal that the time taken in coming back to their final steady state values is very less and the motor overcomes the perturbation with negligible transients. The same is verified through the simulated results.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2008, 14, 1; 67-72
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Soft-Output STBC Decoder for Aeronautical Telemetry
Autorzy:
Louёt, Yves
Othman, Rami
Skrzypczak, Alexandre
Powiązania:
https://bibliotekanauki.pl/articles/309130.pdf
Data publikacji:
2020
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
continuous-phase modulation
CPM
pulse amplitude modulation
PAM
shaped offset quadrature phase shift keying
SOQPSK
space-time block coding
STBC
ternary symbol
Opis:
Alamouti encoding is a well-known space time block encoding technique used to improve the received signal quality in Rayleigh fading channels. In aeronautical telemetry, this encoding technique is applied to shaped offset quadrature phase shift keying tier generation (SOQPSK-TG) modulation in order to handle the two-antenna issue. It is provided for in telemetry-related IRIG standards. In this paper, we propose a unique decoding architecture for Alamouti-encoded SOQPSK-TG signals, taking advantage of pulse amplitude modulation decomposition with soft and hard outputs. We exploit this result to obtain a Viterbi algorithm (VA) for hard decoding and a soft output Viterbi algorithm (SOVA) for soft and hard decoding, with a twofold benefit: operation using one trellis structure, unlike decoders that are based on the 8-waveforms cross-correlated trellis-coded quadrature modulation (XTCQM) approximation, and very attractive bit error rate performance, as well as a complexity trade-off.
Źródło:
Journal of Telecommunications and Information Technology; 2020, 1; 13-20
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of active vibrations damping with the application of active tool
Analiza aktywnej kontroli tłumienia drgań z zastosowaniem aktywnego narzędzia
Autorzy:
Parus, A.
Kasprowiak, M.
Powiązania:
https://bibliotekanauki.pl/articles/94142.pdf
Data publikacji:
2015
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
vibrations damping
active tool
LMS
piezo actuator
external modulation
tłumienie drgań
aktywne narzędzie
piezo siłownik
regeneracja śladu
Opis:
The article represents a short overview of solutions available on the market, which allow for vibrations damping during the machining process. The description also provides information on the essence of chatter vibrations. The next part of the following paper includes the model of active machine tool based on piezoelectric actuator with work piece and the model of machining process. Next, the results of simulation research are presented for two control systems. All simulations were carried out in Matlab Simulink Software.
Artykuł stanowi krótki przegląd rozwiązań dostępnych na rynku, pozwalających tłumić drgania w trakcie obróbki skrawaniem. W opisie można również znaleźć informacje dotyczące istoty drgań samowzbudnych. Kolejną cześć artykułu stanowi model aktywnego narzędzia na bazie piezoelektrycznego siłownika wraz z przedmiotem obrabianym oraz modelem procesu skrawania. Następnie zaprezentowane zostały wyniki badań symulacyjnych dla dwóch układów sterowania (LQG, LMS). Całość symulacji przeprowadzona została w środowisku Matlab Simulink.
Źródło:
Archives of Mechanical Technology and Materials; 2015, 35; 61-69
2450-9469
Pojawia się w:
Archives of Mechanical Technology and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Absorption coefficient along a propagated ultra-short laser pulse in the air based on Kramers–Kronig relations
Autorzy:
Malekshahi, M
Naghavi, K
Powiązania:
https://bibliotekanauki.pl/articles/173894.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ultra-short laser pulse
refractive index
self-phase modulation
absorption coefficient
Kramers–Kronig relations
Opis:
In this manuscript, some effects such as nonlinear Kerr, stimulated Raman, and plasma generation effects lead to obtaining the nonlinear refraction index of the air along an intense ultra-short laser pulse based on one-dimensional propagation analysis. The variations in the pulse frequency by the self-phase modulation effect are investigated for achieving the functionality of the refractive index to the frequency. The mentioned functionality allows implementing Kramers–Kronig relations to measure the absorption coefficient. Results indicate that the front of the laser pulse faces a high rate of the energy loss whereas the back of the pulse experiences a gain. The implementation of Kramers–Kronig relations for a theoretical calculation of absorption coefficient variation along a laser pulse propagating in the air in which we have simultaneously taken into account the three above-mentioned effects distinguishes our work from other studies.
Źródło:
Optica Applicata; 2015, 45, 4; 501-512
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AC power regulation techniques for renewable energy sources
Techniki regulacji mocy odbiorników AC dla odnawialnych źródeł energii
Autorzy:
Ostrowski, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/28875039.pdf
Data publikacji:
2023
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
ac power regulators
pulse width modulation converters
renewable energy systems
regulatory mocy prądu przemiennego
przetwornice modulacji szerokości impulsu
systemy energii odnawialnej
Opis:
This article explores different AC power regulation techniques that can be employed to optimize the output of renewable energy sources, suchas solar and wind power systems. The article provides an overview of the challenges associated with regulating AC power output from renewable sources and examines various techniques that can be used to improve the performance of power regulation systems. These techniques include voltage control, phase control, reactive power compensation, and power factor correction. The article also discusses the benefits and limitations of each technique, as well as their potential applications in renewable energy systems. Overall, this article provides valuable insights for engineers and researchers workingto optimize power auto consumption in renewable energy systems.
W tym artykule omówiono różne techniki regulacji mocy prądu zmiennego, które można wykorzystać do optymalizacji produkcji energiize źródeł odnawialnych, takich jak systemy energii słonecznej i wiatrowej. Artykuł zawiera przegląd wyzwań związanych z regulacją mocy wyjściowej prądu przemiennego ze źródeł odnawialnych i analizuje różne techniki, które można wykorzystać do poprawy wydajności systemów odnawialnych źródeł energii. Techniki te obejmują sterowanie napięciem, sterowanie fazą, kompensację mocy biernej i korekcję współczynnika mocy. W artykule omówiono również zalety i ograniczenia poszczególnych technik, a także ich potencjalne zastosowania w systemach energii odnawialnej. Artykuł zawiera cenne informacje dla inżynierów i badaczy pracujących nad optymalizacją auto konsumpcji energii elektrycznej w systemach energii odnawialnej.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2023, 13, 4; 103--108
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive procedure for automatic modulation recognition
Autorzy:
Liedtke, F.
Powiązania:
https://bibliotekanauki.pl/articles/308334.pdf
Data publikacji:
2004
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
modulation recognition
modulation classification
signal analysis
radio monitoring
Opis:
An adaptive procedure for automatic modulation recognition is described. With it the automatic modulation classification and recognition of radio communication signals with a priori unknown parameters is possible effectively. The results of modulation recognition are important in the context of radio monitoring or electronic support measurements. The special features of the procedure are the possibility to adapt it dynamically to nearly all modulation types, and the capability to recognize continuous phase modulation (CPM) signals like Gaussian minimum-shift keying (GMSK) too. A time synchronization to the symbol rate is not necessary.
Źródło:
Journal of Telecommunications and Information Technology; 2004, 4; 91-97
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
All-optical vestigial sideband carrier suppressed return-to-zero to non-return-to-zero format conversion based on spectral filtering from a cross-phase modulated signal
Autorzy:
Metya, Sanjeev Kumar
Powiązania:
https://bibliotekanauki.pl/articles/173795.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
cross-phase modulation
dispersion shifted fiber
return-to-zero
semiconductor optical amplifier
vestigial sideband carrier suppressed
Opis:
An all-optical vestigial sideband carrier suppressed return-to-zero to non-return-to-zero format conversion is presented with the help of simulation using cross-phase modulation in a nonlinear dispersion shifted fiber. For comparative analysis, a semiconductor optical amplifier based conversion is also considered. Through the process of spectral filtering, the wavelength converted output signal is recovered from a broadened optical spectrum. Error-free conversion of vestigial sideband carrier suppressed return-to-zero pulses to non-return-to-zero format is presented at 10 Gb/s using a 210 − 1 bit sequence and is able to transmit the recovered data through a distance of 50 km having a power penalty of around 1.38 dB in the case of dispersion shifted fiber, whereas a semiconductor optical amplifier performs abysmally.
Źródło:
Optica Applicata; 2019, 49, 2; 275-282
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amplitude and Frequency Modulation in Speaker Recognition Systems
Autorzy:
Ciota, Z.
Powiązania:
https://bibliotekanauki.pl/articles/397977.pdf
Data publikacji:
2012
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
modulacja AM-FM
filtr Gabora
transformata Hilberta
biometryka głosu
spektrogram
przetwarzanie mowy
AM-FM modulation
Gabor filters
Hilbert transform
speaker recognition system
spectrogram analysis
speech processing
Opis:
The paper presents a review of the nowadays methods of voice vector extraction, applied in such speech processing, like person identification and emotion recognition. A special attention was held on mixed time-frequency analysis based on temporary frequency approach. The methods of calculation of time - frequency voice characterization were also described. The most important building blocks of identification and recognition of speakers have been presented. The characterization of feature vectors suitable for identification and verification in microcomputer systems was described. Components and appropriate method of speech identification based on the long-term spectra vectors were discussed.
Źródło:
International Journal of Microelectronics and Computer Science; 2012, 3, 2; 41-44
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An active power filter based on a hybrid converter topology – Part 1
Autorzy:
Gwóźdź, Michał
Ciepliński, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/2173586.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
shunt active power filter
pulse width modulation
PWM
sigma-delta modulator
silicon carbide
bocznikowy filtr mocy czynnej
modulacja szerokości impulsu
modulator sigma-delta
węglik krzemu
Opis:
This paper presents a concept of a shunt active power filter, which is able to provide more precise mapping of its input current drawn from a power line in a reference signal, as compared to a typical filter solution. It can be achieved by means of an interconnection of two separate power electronics converters making, as a whole, a controlled current source, which mainly determines the quality of the shunt active filter operation. One of these power devices, the “auxiliary converter”, corrects the total output current, being a sum of output currents of both converters, toward the reference signal. The rated output power of the auxiliary converter is much lower than the output power of the main one, while its frequency response is extended. Thanks to both these properties and the operation of the auxiliary converter in a continuous mode, pulse modulation components in the filter input current are minimized. Benefits of the filter are paid for by a relatively small increase in the complexity and cost of the system. The proposed solution can be especially attractive for devices with higher output power, where, due to dynamic power loss in power switches, a pulse modulation carrier frequency must be lowered, leading to the limitation of the “frequency response” of the converter. The concept of such a system was called the “hybrid converter topology”. In the first part of the paper, the rules of operation of the active filter based on this topology are presented. Also, the results of comparative studies of filter simulation models based on both typical, i.e. single converter, and hybrid converter topologies, are discussed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 1; art. no. e136218
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An active power filter based on a hybrid converter topology – Part 1
Autorzy:
Gwóźdź, Michał
Ciepliński, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/2090725.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
shunt active power filter
pulse width modulation
PWM
sigma-delta modulator
silicon carbide
bocznikowy filtr mocy czynnej
modulacja szerokości impulsu
modulator sigma-delta
węglik krzemu
Opis:
This paper presents a concept of a shunt active power filter, which is able to provide more precise mapping of its input current drawn from a power line in a reference signal, as compared to a typical filter solution. It can be achieved by means of an interconnection of two separate power electronics converters making, as a whole, a controlled current source, which mainly determines the quality of the shunt active filter operation. One of these power devices, the “auxiliary converter”, corrects the total output current, being a sum of output currents of both converters, toward the reference signal. The rated output power of the auxiliary converter is much lower than the output power of the main one, while its frequency response is extended. Thanks to both these properties and the operation of the auxiliary converter in a continuous mode, pulse modulation components in the filter input current are minimized. Benefits of the filter are paid for by a relatively small increase in the complexity and cost of the system. The proposed solution can be especially attractive for devices with higher output power, where, due to dynamic power loss in power switches, a pulse modulation carrier frequency must be lowered, leading to the limitation of the “frequency response” of the converter. The concept of such a system was called the “hybrid converter topology”. In the first part of the paper, the rules of operation of the active filter based on this topology are presented. Also, the results of comparative studies of filter simulation models based on both typical, i.e. single converter, and hybrid converter topologies, are discussed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 1; e136218, 1--10
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
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