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Tytuł:
Magnetizing current effect minimization in current transformers
Autorzy:
Dusza, D.
Rzepecki, B.
Powiązania:
https://bibliotekanauki.pl/articles/1813967.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
current transformer
value converter
ratio
error minimization
magnetizing current effect
current transformer's error
current measurement
Opis:
Magnetizing current effect minimization in current transformers is considered in this paper. Double-core current transformer operation is described in the following text. The influence of the magnetizing current, which is a significant element of current transformer's error, has been minimized in a new type of double-core current transformer connection. The accuracy evaluation of built double-core current transformer has been carried out according to obtained transformation precision.
Źródło:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały; 2013, 69, 33; 469--476
1733-0718
Pojawia się w:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inductive current transducers in the frequency range up to 150 kHz
Autorzy:
Kosobudzki, G.
Dusza, D.
Powiązania:
https://bibliotekanauki.pl/articles/1193468.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
current
Rogowski coil
inductive current transducer
Opis:
The article presents the results of the research on inductive current transducers in the form of a uniform winding non-magnetic ring with a rigid and flexible construction encompassing the flow of processed current in the frequency range of up to 150 kHz. The results for the developed transducer were related to the results obtained in simulations conducted on the transducer simplified model. The frequency tests of this type of transducers are of key significance in the assessment of the applicability of a given transducer in the measurements of network signals with high-order harmonics, and particularly in the assessment of the construction capacity of inductive current transducers in the form of the Rogowski coil.
Źródło:
Power Electronics and Drives; 2017, 2, 37/2; 167-176
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differential protection with better stabilization for external faults
Zabezpieczenie różnicowe z lepszą stabilizacją dla zwarć zewnętrznych
Autorzy:
Solak, K.
Rebizant, W.
Powiązania:
https://bibliotekanauki.pl/articles/410581.pdf
Data publikacji:
2011
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
current differential criterion
current transformer
fuzzy logic
saturation
Opis:
This paper presents a new differential protection scheme for transmission lines with application of fuzzy signal processing and support of phase comparison criterion. Traditional differential relays may have problems with proper classification of external faults with CT saturation. Better protection stabilization for such cases is obtained with support of fuzzy signal processing. In proposed solution the input signals as well as the standard percentage characteristic are fuzzified. The performance of presented fuzzy protection scheme has been tested with the signals generated with use of EMTP-ATP program and compared to the traditional solution.
W artykule zaprezentowano nowe zabezpieczenie różnicowe, w którym zastosowano rozmyte przetwarzanie sygnałów oraz dodatkowe kryterium porównawczo-fazowe. Proponowane zabezpieczenie jest bardziej odporne na zwarcia zewnętrzne z nasyceniem przekładników prądowych, co potwierdziły przeprowadzone testy. Proponowany algorytm testowany był na sygnałach pochodzących z symulacji w EMTP-ATP, a wyniki porównano ze standardowym przekaźnikiem różnicowym.
Źródło:
Present Problems of Power System Control; 2011, 1; 39-48
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric-active compensation of earth fault current in an IT-type network
Autorzy:
German-Galkin, S.
Hrynkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1193299.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
IT-type networks
earth current
fault current compensation
Opis:
The parametric-active compensation of earth leakage currents which minimalized virtual capacitance current in ships of IT-type network has been discussed. The protection is based on automatic compensation of leakage earth currents. The protection system is governed by a controller. The results of simulation tests have been presented. The parametric-active compensation of earth leakage currents which minimalized virtual capacitance current in ships with IT-type network has been discussed.
Źródło:
Power Electronics and Drives; 2017, 2, 37/1; 81-87
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-Cartesian Frame Transformation-Based Control of a Three-Phase Power Converter During Unbalanced Voltage Dip – Part II: Simulation And Experiment
Autorzy:
Iwański, Grzegorz
Maciejewski, Paweł
Łuszczyk, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1193687.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
AC/DC
power conversion
current control
current limitation
Opis:
The paper presents a control method for the three-phase power converter operating under unbalanced grid voltage conditions. The method uses a new transformation to the non-Cartesian frame, which makes the controlled current vector components balanced in this frame even if originally the three-phase current is referenced as unbalanced. Furthermore, Park’s transformation makes the controlled variables constant, which allows to apply proportional–integral terms as current controllers independent of the required control target. Several control targets known from literature have been analyzed with regard to the required new transformation parameters, and the transformation parameters for all targets have been found. Simulation results are shown to prove the theoretical analysis, and the experimental test results are presented as practical validation of the proposed use of the non-Cartesian frame in control.
Źródło:
Power Electronics and Drives; 2019, 4, 39; 63-77
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Derivation of Motor Mean Phase Currents in PMSM Drives Operating with Low Switching-to-Fundamental Frequency Ratio
Autorzy:
Jarzebowicz, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/1193701.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electric drives
high-speed drives
current control
current measurement
Permanent Magnet Synchronous Drives
Digital Signal Processing
Opis:
Pulse width modulation (PWM) of inverter output voltage causes the waveforms of motor phase currents to consist of distinctive ripples. In order to provide suitable feedback for the motor current controllers, the mean value must be extracted from the currents’ waveforms in every PWM cycle. A common solution to derive the mean phase currents is to sample their value at the midpoint of a symmetrical PWM cycle. Using an assumption of linear current changes in steady PWM subintervals, this midpoint sample corresponds to the mean current in the PWM cycle. This way no hardware filtering or high-rate current sampling is required. Nevertheless, the assumption of linear current changes has been recently reported as over simplistic in permanent magnet synchronous motor (PMSM) drives operating with low switching-to-fundamental frequency ratio (SFFR). This, in turn, causes substantial errors in the representation of the mean phase currents by the midpoint sample. This paper proposes a solution for deriving mean phase currents in low SFFR PMSM drives, which does not rely on the linear current change assumption. The method is based on sampling the currents at the start point of a PWM cycle and correcting the sampled value using a model-based formula that reproduces the current waveforms. Effectiveness of the method is verified by simulation for an exemplary setup of high-speed PMSM drive. The results show that the proposed method decreases the error of determining the mean phase currents approximately 10 times when compared to the classical midpoint sampling technique.
Źródło:
Power Electronics and Drives; 2019, 4, 39; 95-102
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Current-voltage characteristic and electroluminescence of UV LEDs 365 nm at liquid nitrogen temperature
Autorzy:
Veleschuk, Vitaly
Vlasenko, Alexander
Vlasenko, Zoya
Petrenko, Ihor
Malyi, Yevhen
Borshch, Vladimir
Borshch, Olena
Shefer, Alexander
Powiązania:
https://bibliotekanauki.pl/articles/174330.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
S-shaped current-voltage characteristic
UV LED
Opis:
For InGaN/AlGaN/GaN ultraviolet (λ = 365 nm) light emitting diodes, the S-shaped current-voltage characteristic was observed at liquid nitrogen temperature due to the transition from single injection (electrons) to double (electrons and holes) injection. Initially only electron injection into the active region takes place and as the current is increased, the injection of holes starts. It has been found that at the voltage of the minimum of the negative differential resistance region, oscillations of the current, accompanied by increasing electroluminescence intensity arise, and the repetition rate of the oscillations increases with the direct current rise. The intensity of the main ultraviolet and yellow electroluminescence bands sharply increases with increasing current at negative differential resistance region due to the rise of holes injection.
Źródło:
Optica Applicata; 2019, 49, 1; 125-133
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibilities for determining the interference between a power supply network and a converter fed drive
Autorzy:
Beniak, R.
Gardecki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1193393.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
power quality
converter drives
voltage and current measurements
Opis:
Measuring instruments, measurement methods, and an exemplary analysis of the impact of chosen operating stages of the converter drive on the power supply network have been presented. The measurements of electrical and mechanical parameters in drive systems used in industry are complex. The task is difficult due to the necessity of connecting a measuring instrument into electric circuits of an active facility with the use of only short non-operational periods of the device. However, a wellchosen model of a drive system allows the multivariate research of the impact of drive parameters and a control algorithm used on voltage and current harmonic content and performance of the system, and therefore on a simulation analysis of the impact of the drive on the power supply network.
Źródło:
Power Electronics and Drives; 2017, 2, 37/1; 17-26
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-Cartesian Frame Transformation-Based Control of a Three-Phase Power Converter During Unbalanced Voltage Dip – Part I: Transformation Principles
Autorzy:
Iwański, Grzegorz
Maciejewski, Paweł
Łuszczyk, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1193698.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
AC/DC
power conversion
current control
Clarke's transformation
Opis:
One of the currently investigated problems in power electronics-based electrical energy conversion is proper operation of electronic converters during grid voltage imbalance and harmonics. In classic control methods, it introduces oscillations of variables, resulting in the necessity to improve control systems with signals filtration and usually by application of resonant terms as part of current controllers. The paper presents a new approach to grid-connected inverter control based on transformation to a non-Cartesian frame, the parameters of which are correlated with grid voltage asymmetry. The proposed method results in resignation from resonant terms used as controllers and their replacement with proportional–integral terms for which anti-wind-up structures are significantly simpler than for oscillatory terms. The paper presents new transformation principles, features and some simulation results showing the waveforms of signals transformed to the new non-Cartesian frame.
Źródło:
Power Electronics and Drives; 2019, 4, 39; 47-61
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compensation methods of current and speed sensor faults for a vector controlled induction motor drive system
Autorzy:
Klimkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1193297.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
DFOC
speed sensor
current sensor
detector
fault tolerant drive
Opis:
Chosen speed and current sensor fault detectors for a vector controlled induction motor drive system have been presented. Systems based on the artificial intelligence (neural network) and simple algorithmic systems were analyzed and tested in various drive conditions. The influence of chosen sensor faults on performance of the drive system has been presented. The compensation strategy was proposed and tested. A fault tolerant drive, based on hardware redundancy, has been developed and presented. Simulation and experimental results are obtained in direct field oriented control algorithm (DFOC) on the laboratory set-up with rapid prototyping card Micro Lab Box DS1202 by dSpace.
Źródło:
Power Electronics and Drives; 2017, 2, 37/1; 57-69
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of externally adding pyrite and electrical current on galvanic leaching of chalcopyrite concentrate
Autorzy:
Asgari, Kaveh
Hassanzadeh, Ahmad
Nazari, Sabereh
Vakylabad, Ali Behrad
Hosseinzadeh, Mostafa
Powiązania:
https://bibliotekanauki.pl/articles/1447957.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
copper concentrate
galvanic leaching
pyrite
electrical current
leaching kinetics
Opis:
Although the operating properties of GalvanoxTM leaching have been widely studied in the literature, several factors concerning chalcopyrite passivation during the process remain unknown so far. The present work hence aims at investigating the significant effect of externally added pyrite features with a particular focus on its particle size (d80 of 0.52, 20, 45 and 2000 µm) through a series of experiments performed in a 2-L stirred-tank electro-reactor. To this end, the role of pyrite: chalcopyrite ratio (0.49:1, 2:1 and 4:1) and presence of electrical current were examined while the rest of the parameters kept constant (80 °C temperature, 400–500 mV (Ag/AgCl) redox potential, pulp density of 10% (w/v), and stirring rate of 1200 rpm). Plus, kinetic models of the leaching tests were studied based on the diffusion and chemical controlling concepts. It was found that the coarser the pyrite particles, the more favorable the copper extraction from the concentrate due to acceleration of reactions in the cathodic electrode and high mass transfers. However, this was in contradiction with the existing reports in the literature. Moreover, galvanic interactions became intensive in the presence of pyrite meaning extensive chalcopyrite dissolution with significantly reduced passivation. Ultimate copper extraction values of 24.17±1.25%, 55.79±0.91% and 57.26±1.59% were resulted at Py:Cp ratios of 0.49:1 (natural), 2:1 and 4:1, respectively. The results showed that maximum copper recovery of 67.32±2.34% was obtained at an optimum condition of pyrite grain size=2000 µm, Py:Cp=4:1, current application=500 mA, 8 h and 80 °C. Finally, detailed kinetic modeling indicated that the chemical control mechanism was dominant in the early reaction stages (t<3.5 h) concerning the availability of fresh surface for chemical agents; however, the second half of the process (8.0 h>t>3.5 h) was controlled by the diffusion control.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 2; 105-119
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simple and precise method for the threshold current determination in vertical-cavity surface-emitting lasers
Autorzy:
Pruszyńska-Karbownik, Emilia
Gębski, Marcin
Marciniak, Magdalena
Lott, James A.
Czyszanowski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/174774.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
VCSEL
vertical-cavity surface-emitting laser
threshold current
spontaneous emission
Opis:
In this paper, we present experimental results of spontaneous emission clamping in the threshold for vertical-cavity surface-emitting lasers (VCSELs) with oxide current confinement. We show that the spontaneous emission not wholly clamps in the threshold. We propose a new method for determining the threshold current value using the study of the clamping phenomena. This method has an advantage over the commonly used methods in the accuracy because the current of the spontaneous emission clamping is betted defined than the current of the slope change of the stimulated emission light-current curve. The estimated uncertainty of the method is no more than 20 μA.
Źródło:
Optica Applicata; 2020, 50, 2; 281-288
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synchrogenverter - parallel connection of synchronous generator and power converter with energy storage
Autorzy:
Szulawski, P.
Koczara, W.
Powiązania:
https://bibliotekanauki.pl/articles/1193215.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
synchronous generator
power electronic converter
synchrogenverter
energy storage current control
Opis:
The paper describes novel power generation topology wherein synchronous generator have a parallel connected power electronic converter. In this arrangement synchronous generator is only source of active power and power electronic converter is source of reactive power. Such power distribution allows to increase the synchronous generator generated active power by 25%, and operate with unity power factor. The power converter with energy storage system embedded can deliver additional active power in transient state to improve generator stability.
Źródło:
Power Electronics and Drives; 2016, 1, 36/1; 69-78
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extended Feedback Linearisation Control of Non-ideal DCDC Buck Converter in Continuous-conduction Mode
Autorzy:
Csizmadia, Miklos
Kuczmann, Miklos
Powiązania:
https://bibliotekanauki.pl/articles/2175943.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
DC-DC buck converter
feedback linearisation
inrush current
parasitics
Ackermann
Opis:
This paper presents an extended form of Feedback Linearisation Control (FBLC), which is tested in a non-ideal buck converter in Continuous-conduction Mode (CCM). The FBLC is often used in power electronics to control a non-linear system, due to its advantageous properties. The application of the error integrator shows better steady-state and transient properties, such as a decrease of inrush current. The linearised system has been controlled by the pole placement and the technique is illustrated through an example and simulated via Matlab. The results have been compared by using a classical PID controller, allowing the benefits of FBLC to be highlighted.
Źródło:
Power Electronics and Drives; 2022, 7, 42; 1--8
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of grid disturbances on current source rectifier controlled by FCS-MPC algorithm
Autorzy:
Godlewska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1193668.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
active front end
current source rectifier
model predictive control
active damping
Opis:
Nowadays, the increasing number of non-linear loads influences the grid, causing grid voltage disturbances. These disturbances may be very dangerous for the equipment and can create faults in converter behaviour. However, the right control algorithm can improve the reliability of the work. For a current source rectifier, the finite control set model predictive control has been proposed. This method is very flexible because of the variety of the possible cost function forms. It has been examined under grid voltage disturbed by the higher harmonics and the voltage drop. Simulation results prove the ability to damp the distortions and to ensure the unity power factor. Summing up, the algorithm is a very good solution for use in applications such as battery charging, active power filtering and low-voltage direct current load feeding.
Źródło:
Power Electronics and Drives; 2018, 3, 38; 11-22
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 24

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