Wyniki wyszukiwania - Biblioteka Nauki

1

Energy conversion in small water plants with variable speed PM generator

100%

Sobczyk T. , Węgiel T. , Mazgaj W. , Szular Z.

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2

Active compensation in PWM rectifier system

100%

Jankowski J. , Łuczkowski R.

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2007

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tom No 53

89-99

EN

In this paper, three phase classical rectifier and PWM control rectifier simulation model together with different structures of compensation and filtering systems: capacitor battery and shunt active filter are presented. The investigations concern the effectiveness of harmonic filtration the phase current network in conditions when network phase voltage is deformation and unbalance. Based on examinations simulation executed the opinion of individual converters structures.

3

Parameter independent encoderless control of servo drives without additional hardware components

88%

Kennel R. , Ferreira R. , Szczupak P.

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2006

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tom Vol. 54, nr 3

327-333

EN

A lot of methods for sensorless drive control have been published last years for synchronous and asynchronous machines. One of the approaches uses high frequency carrier injection for position control. The injected high frequency signal is controlled to remain in alignment with the saliency produced by the saturation of the main flux. Due to the fact that it does not use the fundamental machine model which fails at standstill of the magnetic field it is possible to control the drive even at zero speed. In spite of this obvious advantage industry does not apply sensorless control in their products. This is due to the dependency of many published methods on physical parameters of the machine. The high frequency carrier injection method, presented in this paper, does not need to have exact machine parameters and it can be used for machines where there is only a very small ro-tor anisotropy like in Surface Mounted Permanent Magnet Synchronous Machines (SM-PMSM) [1]. Standard drives usually are supplied by a 6-pulse diode rectifier. Due to new European directives concerning the harmonic content in the mains it is expected that the use of controlled pulse-width modulated PWM rectifiers will be enforced in the future [2]. An important advantage of this type of rectifiers is the regeneration of the energy back to the grid. Another benefit are Iow harmonics in comparison to diode rectifiers. Using one of many control methods published so far it is also possible to achieve almost unity power factor. However, in these methods voltage sensors are necessary to synchronize PWM rectifiers with the mains. Therefore they are not very popular in the industry with respect to the cost and the lack of reliability. Recently a control method was proposed which is based on a tracking scheme. It does not need any voltage sensor on the acside of the rectifier and it does not need to know accurate parameters of the system. This paper presents the control solution for a cheap, industry friendly (no additional hardware and installation effort) drive system. The phase tracking method for control of electrical drive and PWM rectifier is described. Encouraging experimental results are shown.

4

Modelowanie propagacji i filtracji zniekształceń w lokalnych sieciach elektroenergetycznych

75%

Iwan K.

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2010

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tom R. 86, nr 3

117-119

PL

W referacie opisano przykład wpływu pracy UPS o mocy 30 kVA na sieć zasilającą i odbiorczą. Prostownik typu boost PWM pobiera prąd o znacznej zawartości harmonicznych przy podstawowej częstotliwości 11 kHz i jest źródłem zaburzeń propagowanych na obwody odbiorcze. Za cel pracy przyjęto odwzorowanie obserwowanych procesów generacji i propagacji zaburzeń za pomocą modelowania obwodowego.

5

Układ sterowania przekształtnikiem sieciowym z funkcją filtru aktywnego z estymacją zastępczej SEM sieci

63%

Wojciechowski D.

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2006

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tom Vol. 47, nr 1

24-27

PL

Przedstawiono układ sterowania przekształtnikiem sieciowym z funkcją filtru aktywnego. Układ zapewnia skuteczność filtracji ograniczoną jedynie parametrami obwodów elektrycznych. Zadanie to realizowane jest z zastosowaniem algorytmów predykcyjnych: bezczujnikowej estymacji zastępczej SEM sieci, wyznaczania prądów fazowych oraz regulatora prądów fazowych. Regulacja napięcia w obwodzie prądu stałego realizowana jest z wykorzystaniem regulatora Pl o zmiennym wzmocnieniu proporcjonalnym, zapewniającego szybką regulację napięcia w stanach przejściowych oraz małe wzmocnienie dla oscylacji tego napięcia w stanie ustalonym.

EN

In the paper the control system of the PWM rectifier with active filtering is presented. Proposed system provides effectiveness of filtering which is limited only by circuit parameters. This task is realized using predictive algorithms of: estimator of grid emf, set grid currents calculation and currents controller. The DC voltage is controlled by proposed variable gain PI controller, which ensures fast control in transients and low gain for steady state oscillations of this voltage. Experimental results achieved for 7 kVA prototype of PWM rectifier are presented.

6

Comparative Study of PI and Fuzzy DC Voltage Control for a DPC- PWM Rectifier

51%

Semmah A. , Massoum A. , Hamdaoui H. , Wira P.

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2011

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tom R. 87, nr 10

355-359

EN

This paper treats control strategies of a pulse width modulation (PWM) rectifier to eliminate harmonics currents and consequently to reduce total harmonic distortion of the line current and improve power factor. It is about the use of direct control principle to control instantaneous active and reactive powers. Such a technique is called direct power control (DPC). The principal idea of DPC was suggested initially by Ohnishi (1991) and developed then by Noguchi and Takahachi in 1998. This concept is similar to DTC applied to induction motors. A comparative study, concerning the DC voltage control, will be given in this study. It is about the use of a PI controller and a fuzzy logic one to ensure a stable active power exchange. A digital simulation, in Matlab/Simulink/SimPowerSystems and Fuzzy Logic Toolbox, was carried out and given in the end of this paper. The simulation results show clearly the supremacy of the technique adopted to control the DC voltage.

PL

Analizowano różne strategie przekształtnika PWM umożliwiające eliminację prądów harmonicznych a w konsekcencjio poprawę współczynnika THD. Zastosowano technikę SPC – direct power control. Wykorzystano kontrolery PI i logiki rozmytej. Metody oceniono przeprowadzając symulacje.