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Wyszukujesz frazę "high-frequency" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Improving sensitivity of residual current transformers to high frequency earth fault currents
Autorzy:
Czapp, S.
Dobrzyński, K.
Klucznik, J.
Lubosny, Z.
Kowalak, R.
Powiązania:
https://bibliotekanauki.pl/articles/141169.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
current transformers
earth fault currents
electric devices
electromagnetic couplings
high frequency
Opis:
For protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed the modification in the structure of residual current devices. This modification improves sensitivity of residual current devices when high frequency earth fault current occurs. The test of the modified residual current device proved that the authors’ proposition is appropriate.
Źródło:
Archives of Electrical Engineering; 2017, 66, 3; 485-494
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel circuit topology of modified switched boost hybrid resonant inverter fitted induction heating equipment
Autorzy:
Bhattacharya, A.
Sit, K.
Sadhu, P. K.
Pal, N.
Powiązania:
https://bibliotekanauki.pl/articles/140770.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
modified switched boost
high frequency
hybrid resonant inverter
induction heating
controllability
VSI and PSIM
Opis:
A novel circuit topology of modified switched boost high frequency hybrid resonant inverter fitted induction heating equipment is presented in this paper for efficient induction heating. Recently, induction heating technique is becoming very popular for both domestic and industrial purposes because of its high energy efficiency and controllability. Generally in induction heating, a high frequency alternating magnetic field is required to induce the eddy currents in the work piece. High frequency resonant inverters are incorporated in induction heating equipment which produce a high frequency alternating magnetic field surrounding the coil. Previously this high frequency alternating magnetic field was produced by voltage source inverters. But VSIs have several demerits. So, in this paper, a new scheme of modified switched boost high frequency hybrid resonant inverter fitted induction heating equipment has been depicted which enhances the energy efficiency and controllability and the same is validated by PSIM.
Źródło:
Archives of Electrical Engineering; 2016, 65, 4; 815-826
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-voltage overhead lines topology identification method based on high-frequency signal injection
Autorzy:
Ge, Haotian
Xu, Bingyin
Zhang, Xinhui
Bi, Yongjian
Powiązania:
https://bibliotekanauki.pl/articles/1955180.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high-frequency signal injection
low voltage overhead lines
topology identification
wtrysk sygnału wysokiej częstotliwości
linie napowietrzne niskiego napięcia
identyfikacja topologii
Opis:
The topology of low-voltage distribution systems changes with the load or the on/off position of the circuit switch. This will affect power flows, losses, and so on. This paper submits a new method to identify the topology of a low-voltage feeder using the injection high-frequency signal. An inductor can block the high-frequency signal. It can change the propagation direction of the injected high-frequency signal to make it propagate unidirectionally along the low-voltage feeder. By injecting a 5 MHz sinusoidal signal from the upstream direction of the low-voltage feeder, all the line segments and devices on the feeder can be identified. The wavelength of the high-frequency signal is short. The wavelength of the 5 MHz signal is 60 meters. Through the delay of different observation points on the feeder, the length of the line section can be roughly calculated. The high- frequency signal has an obvious reflection on the feeder. Using this feature, we can roughly calculate the length of the line segment. The correctness of the method is demonstrated by MATLAB simulation verification.
Źródło:
Archives of Electrical Engineering; 2021, 70, 4; 791-800
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of the AC/HF/DC converter with power factor correction
Autorzy:
Bogdan, A.
Powiązania:
https://bibliotekanauki.pl/articles/141404.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
korekcja współczynnika mocy
obwód rezonansowy
transformator wysokiej częstotliwości
przekształtnik podwyższający napięcie
power factor correction
resonant circuit
high frequency transformer
boost converter
Opis:
In this paper, the power factor correction system consisted of: bridge converter, parallel resonant circuit, high frequency transformer, diode rectifier and LFCF filter is presented. This system is controlled by a pulse density modulation method and the principle of its operation is based on the boost technique. The modeling approach is illustrated by an example using AC/HF/DC converter. Verification of the derived model is provided, which demonstrated the validity of the proposed approach.
Źródło:
Archives of Electrical Engineering; 2010, 59, 3-4; 141-152
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of non-linear losses in an integrated contactless power supply for magnetically levitated elevator systems using discrete circuit elements
Autorzy:
Putri, A. K.
Appunn, R.
Hameyer, K.
Powiązania:
https://bibliotekanauki.pl/articles/141742.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
contactless energy transmission
electromagnetic guiding system
equivalent circuit model
ferromagnetic material at high frequency
magnetically levitated elevator
modelling of non-linear losses
Opis:
A contactless energy transmission system is essential to supply onboard systems of electromagnetically levitated vehicles without physical contact to the guide rail. One of the possibilities to realise a contactless power supply (CPS) is by integrating the primary actuator into the guide rail of an electromagnetic guiding system (MGS). The secondary actuator is mounted on the elevator car. During the energy transmission, load dependent non-linear losses occur in the guide rail. The additional losses, which are caused by the leakage flux penetrating into the guide rail, cannot be modelled using the classical approach of iron losses in the equivalent circuit of a transformer, which is a constant parallel resistance to the mutual inductance. This paper introduces an approach for modelling the load dependent non-linear losses occurring in the guide rail using additional variable discrete circuit elements.
Źródło:
Archives of Electrical Engineering; 2015, 64, 2; 177-187
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An approach to suppress high-frequency resonance using model predictive and selective harmonic elimination combined strategy
Autorzy:
Chen, Sitong
Chen, Xiaoqiang
Wang, Ying
Xiong, Ye
Powiązania:
https://bibliotekanauki.pl/articles/1841300.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CRH5 EMUs and traction power supply coupled system
high-frequency oscillation
high speed railway
model predictive control (MPC)
selective harmonic elimination pulse-width modulation (SHEPWM)
CRH5 EMU i system sprzężony z zasilaniem trakcyjnym
oscylacja wysokiej częstotliwości
kolej dużych prędkości
kontrola predykcyjna modelu (MPC)
selektywna eliminacja harmoniczna modulacja szerokości impulsu (SHEPWM)
Opis:
High-frequency resonance is a prominent phenomenon which affects the normal operation of the high-speed railway in China. Aiming at this problem, the resonance mechanism is analyzed first. Then, model predictive control and selective harmonic elimination pulse-width modulation (MPC-SHEPWM) combined control strategy is proposed, where the harmonics which cause the resonance can be eliminated at the harmonic source. Besides, the MPC is combined to make the current track the reference in transients. The proposed control has the ability to suppress the resonance while has a faster dynamic performance comparing with SHEPWM. Finally, the proposed MPC-SHEPWM is tested in a simulation model of CRH5 (Chinese Railway High-speed), EMUs (electric multiple units) and a traction power supply coupled system, which shows that the proposed MPC-SHEPWM approach can achieve the resonance suppression and shows a better dynamic performance.
Źródło:
Archives of Electrical Engineering; 2021, 70, 2; 415-430
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the operational performance of high speed permanent magnet generator with controlled rectifier in distributed generation
Autorzy:
Hongbo, Q.
Yanqi, W.
Cunxiang, Y.
Kaiqiang, H.
Powiązania:
https://bibliotekanauki.pl/articles/140696.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high speed permanent magnet generator
controlled rectifier
electromagnetic field
switching frequency
Opis:
The uncontrolled rectifier and controlled rectifier which use fixed switching frequency control strategy are applied usually during the working of a high-power high- speed permanent magnet generator (HSPMG). Even for the controlled rectifier, it will generate harmonics. The electromagnetic performance of the HSPMG is also affected by these harmonics. In this paper, the influences of the fixed switching frequency control strategy on a HSPMG were studied. Based on the Fourier theory, the harmonic currents of the generator were analyzed, and the change of harmonic distribution range and current total harmonic distortion (THD) were obtained. By using an indirect field-circuit coupling method, the influences of the fixed switching frequency control strategy on the losses and torque of the generator were analyzed. The relations between the switching frequency and the losses and torque of the generator were obtained, and the change mechanism of the loss was revealed. The obtained conclusions can provide reference for the optimized choice of the switching frequency of the distributed generation system with the HSPMG. It can also provide support for the HSPMG electromagnetic structural optimization and the optimization of the loss and harmonic on the system level.
Źródło:
Archives of Electrical Engineering; 2018, 67, 4; 899-913
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the influence of power frequency electric field of pantograph on passengers’ health in high-speed EMU
Autorzy:
Tian, Rui
Zhang, Jia-Qi
Lu, Mai
Powiązania:
https://bibliotekanauki.pl/articles/24202736.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
induced current density
induced electric field intensity
high-speed EMU
pantograph
power frequency electric field
Opis:
In this work we discussed the safety of the electric field environment in the No. 3 carriage where the pantograph is located. DSA380 pantograph, CRH5 EMU carriage and passengers’ models were established to study the electric field exposure of passengers at different positions. The results showed that Emax in the carriage without passengers is 1.173 x 10 6 mV/m. Then we set the passengers’ positions according to the electric field distribution in the carriage without passengers and obtained that Emax in the carriage with passengers is 3.195 x 10 6 mV/m. It can be seen that the maximum induced electric field intensity of passengers at different positions appears on the soles of shoes, the maximum value is 3.028 x 105 mV/m, the maximum induced current density occurs at the ankle, its maximum value is 3.476 x 10 -5 A/m 2. It can be concluded that the maximum induced electric field intensity of passenger’s head appears in the cerebrospinal fluid area, with a maximum value of 202.817 mV/m, and the maximum induced electric field intensity of passenger’s head at the door is larger than that in the middle of the carriage. The maximum values of the induced electric field intensity in all tissues of passengers are much smaller than the basic limits of electromagnetic exposure to the public set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). This study indicated that the pantograph has little influence on the electric field environment in the carriage under working state, and will not cause any health hazard to the passengers in this working frequency electric field environment.
Źródło:
Archives of Electrical Engineering; 2023, 72, 2; 483--501
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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