Temat: three-phase - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Error analysis of the three-phase electrical energy calculation method in the case of voltage-loss failure
Autorzy:: Cheng, Han-miao
Wang, Zhong-dong
Cai, Qi-xin
Lu, Xiao-quan
Gao, Yu-xiang
Song, Rui-peng
Tian, Zheng-qi
Mu, Xiao-xing
Tematy:: three-phase electrical energy meter
voltage-loss failure
voltage substitution
three-phase voltage unbalance
calculation error; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/221096.pdf Link otwiera się w nowym oknie
Opis:: The single-phase voltage loss is a common fault. Once the voltage-loss failure occurs, the amount of electrical energy will not be measured, but it is to be calculated so as to protect the interest of the power supplier. Two automatic calculation methods, the power substitution and the voltage substitution, are introduced in this paper. Considering the lack of quantitative analysis of the calculation error of the voltage substitution method, the grid traversal method and MATLAB tool are applied to solve the problem. The theoretical analysis indicates that the calculation error is closely related to the voltage unbalance factor and the power factor, and the maximum calculation error is about 6% when the power system operates normally. To verify the theoretical analysis, two three-phase electrical energy metering devices have been developed, and verification tests have been carried out in both the lab and field conditions. The lab testing results are consistent with the theoretical ones, and the field testing results show that the calculation errors are generally below 0.2%, that is correct in most cases.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Novel arrangement of combined star-delta stator winding aimed at reduction of copper usage in electric machine
Nowy układ uzwojenia mieszanego gwiazda-trójkąt w stojanie zmniejszający zużycie miedzi w maszynie elektrycznej
Autorzy:: Schreier, L.
Bendl, J.
Chomat, M.
Tematy:: electric machine
stator
three-phase winding; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Napędów i Maszyn Elektrycznych Komel
Powiązania:: https://bibliotekanauki.pl/articles/1197468.pdf Link otwiera się w nowym oknie
Opis:: The submitted paper deals with the increased energy efficiency of induction machines by means of the so-called combined stator winding. Two basic variants of this winding, the series and parallel ones, are shown. The suppression of higher harmonics is analysed by means of the method of space vectors and symmetrical components. It is shown that the so-called series variant of the combined winding has a better ability to suppress higher spatial harmonics. The commonly used combined winding has, however, a longer pitch and thus bigger stator resistance and greater consumption of copper. The paper presents a proposal of an adapted combined winding whose pitch is smaller than that of the used three-phase winding. This fact results in decreasing the consumption of copper conductors with preserving the energy efficiency. The results of the analysis have been verified by measurements on physical models of machines with the combined and the adapted combined windings.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Three phase partitioning as a rapid and efficient method for purification of plant-esterase from wheat flour
Autorzy:: Dong, Liang
He, Linxin
Huo, Danqun
Tematy:: Purification
Plant esterase
Three phase partitioning; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/778983.pdf Link otwiera się w nowym oknie
Opis:: Three-phase partitioning (TPP) was used to purify plant-esterase from wheat flour. Effect of various process parameters has been evaluated and plant-esterase was purified to 11.35-fold by optimized single step TPP system (50%, (w/v) (NH₄)₂ SO₄ saturation, 1:1 (v/v) ratio of crude extract: t-butanol at pH 4).The enzyme was found to be exclusively partitioned in the aqueous phase. Using TPP system, plant-esterase quickly purified to homogeneity with very high purity and activity. On the basis of single factor research, purification process was optimized by using response surface method, established a new type of high effcient purification plant-esterase method. To the best of our knowledge, this is the first report for purification and characterization of plant-esterase by using three phase partitioning (TPP). The results indicated that, TPP is a simple, quick, economical and very attractive process for purification of plant-esterase compared to conventional chromatographic protocols.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: The Execution of New Interleaved Single-Stage of Three-Phase Ac-Dc Converter with Power Factor Correction Using Space Shift Pulse Width Modulation
Autorzy:: Sowntharya, S.
Sureshkumar, R.
Tematy:: AC-DC converter
power factor correction
space vector phase-shifted modulation
three-phase converter
three-phase system
transformer circuit; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1192665.pdf Link otwiera się w nowym oknie
Opis:: In this project is addressed to the function of AC-DC converter operation and its modulation techniques. In recent years to developing pulse width modulation to used power conversion process. The many techniques of PWM to improve power production program. In this project focused Addresses a cost-effective, flexible solution of improvement of efficiency to three phase AC-DC converter using SVPWM(space vector pulse width modulation).The proposed converter has a better efficiency, especially under light-load condition and it was explained that this is because the energy from the output inductor can always be used to ensure that the very top and the very bottom switches can be turned ON with ZVS due to a discharge path that is introduced by its flying capacitor.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Mikrofiltracja z podawaniem nadawy płynącej wraz z pęcherzykami powietrza
Microfiltration with the feed containing air bubbles
Autorzy:: Szwast, M.
Szwast, Z.
Tematy:: mikrofiltracja
nadawa trójfazowa
microfiltration
three-phase feed; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/2073048.pdf Link otwiera się w nowym oknie
Opis:: Zbadano krzyżowy układ mikrofiltracyjny do zagęszczania zawiesin rozdrobnionego ciała stałego w cieczy zasilany nadawą płynącą wraz z pęcherzykami powietrza. Nie stwierdzono wpływu pęcherzyków na przebieg procesu, co oznacza, że pozytywne oddziaływanie pęcherzyków przejawiające się w zmywaniu osadu i negatywne przejawiające się w blokowaniu przez pęcherzyki dostępu cieczy do części powierzchni membrany, wzajemnie znoszą się. Wykazano też, że literaturowa zależność strumienia permeatu od stężenia zawiesiny dla nadawy dwufazowej jest aktualna także dla nadawy trójfazowej.
Cross-flow microfiltration used for concentrating solid particles suspension with the addition of gas bubbles in the feed was investigated. The impact of gas bubbles on microfiltration process was not observed. This means that the positive impact of gas bubbles manifested in deposit washing from the membrane surface and the negative impact exhibited by blocking the liquid access to the membrane surface, cancel each other. It was proven that the literature relationship between permeate flow and suspension concentration for the two-phase feed is valid also for the three-phase feed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Three-phase contact line expansion during air bubble attachment to hydrophobic solid surface – experiment and modeling
Autorzy:: Basarova, P.
Soušková, K.
Zawala, J.
Tematy:: Attachment
simulations
bubble
three-phase contact
dewetting; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110269.pdf Link otwiera się w nowym oknie
Opis:: Kinetics of spreading of the three-phase contact hole (dewetting) formed by an air bubble colliding with hydrophobic solid surface, after rupture of intervening liquid film, was studied both experimentally and numerically. During experiments it was found that evolution of the TPC line diameter with time occurs with characteristic S-shaped trend which, in consequence, causing rather unexpected maxima at the TPC line spreading velocity curves. It was determined that position of this maximum appears after 1-2 ms after TPC hole formation and its position (in respect to time) depends on the bubble diameter. In solution of surface-active substance this maximum was much smoother and longer. By means of complementary numerical calculations the source of maxima existence and differences in their position and shapes were explained. It was concluded that this effect has only hydrodynamic origin, caused by different course of bubble shape pulsations during TPC line formation and spreading, which depends on degree of liquid/gas interface immobilization (fluidity retardation).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Dynamic states of three-phase induction motors. Selected problems
Autorzy:: Nawrowski, R.
Stein, Z.
Zielinska, M J
Tematy:: induction motor
dynamic states
three-phase induction motor; Pokaż więcej
Wydawca:: Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:: https://bibliotekanauki.pl/articles/97485.pdf Link otwiera się w nowym oknie
Opis:: The paper presents some problems arising during dynamic processes undergoing in three-phase induction motors, particularly in some asymmetric connection modes. Some characteristics illustrating the machine behaviour, particularly during start-up and at asymmetric connection modes, are presented with the use of basic differential equations describing operation of three-phase induction motors.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: A predictive estimation based control strategy for a quasi-resonant dc-link inverter
Autorzy:: Turzyński, M.
Banach, P.
Murawski, P.
Pepliński, R.
Chrzan, P. J.
Tematy:: resonant converters
ZVS three-phase inverter
current estimation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/200484.pdf Link otwiera się w nowym oknie
Opis:: Control of parallel quasi resonant dc link inverters (PQRDCLI) is usually based on dc link input inverter current. Instead of a direct measurement of this noise sensitive and fast changing current signal - its estimation with one step prediction may be considered. Estimation of an input inverter current is based on inverter output current measurements, applied in most of power electronics controlled ac drives. In this paper, the PQRDCLI fed induction motor (IM) with a predictive current estimation stabilizes resonant inverter output voltage slopes du/dt independently of load. By control of output voltage derivatives, reduction of overvoltage spikes and common mode motor currents is achieved. An analysis of the PQRDCLI control with a predictive current estimation strategy is verified by the Saber system simulation and experimental tests in a laboratory setup.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Trójfazowy generator z magnesami trwałymi w reżimie pracy jednofazowej
Tree phase permanent magnet generator assigned to single-phase work
Autorzy:: Rossa, R.
Pistelok, P.
Tematy:: trójfazowy generator
praca jednofazowa
three phase permanent
single-phase work; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Napędów i Maszyn Elektrycznych Komel
Powiązania:: https://bibliotekanauki.pl/articles/1369584.pdf Link otwiera się w nowym oknie
Opis:: The article presents the concept of an electromagnetic circuit generator with permanent magnets mounted on the surface rotor core designed for single phase work. Computation field-circuit model was shown. The spectrum of time course of voltages in the idle work was presented. The cross section with graphically presentation of magnetic induction in particular parts of electromagnetic circuits was presented. Distribution of magnetic induction at the rated load point for each phase were shown. The time course of voltages and currents for each phases for rated power were displayed. An analysis of laboratory results and measurement of load characteristics of the generator was discussed. The work deals with three electromagnetic circuits of generators with permanent magnet where output voltage characteristics versus rated power were expressed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Improved modeling of new three-phase high voltage transformer with magnetic shunts
Autorzy:: Chraygane, M.
El Ghazal, N.
Fadel, M.
Bahani, B.
Belhaiba, A.
Ferfra, M.
Bassoui, M.
Tematy:: transformer
three-phase
modeling
EMTP
microwaves
power supply; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/950652.pdf Link otwiera się w nowym oknie
Opis:: This original paper deals with a new approach for the study of behavior in nonlinear regime of a new three-phase high voltage power supply for magnetrons, used for the microwave generators in industrial applications. The design of this system is composed of a new three-phase leakage flux transformer supplying by phase a cell, composed of a capacitor and a diode, which multiplies the voltage and stabilizes the current. Each cell. in turn, supplies a single magnetron. An equivalent model of this transformer is developed taking into account the saturation phenomenon and the stabilization process of each magnetron. Each inductance of the model is characterized by a non linear relation between flux and current. This model was tested by EMTP software near the nominal state. The theoretical results were compared to experimental measurements with a good agreement. Relative to the current device, the new systemprovides gains of size, volume, cost of implementation and maintenance which make it more economical.
Dostawca treści:: Biblioteka Nauki

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