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Minimalizacja prądu jałowego transformatora w stanie asymetrii napięć fazowych z wykorzystaniem przekształtników czterogałęziowych

Stefańczak Bartłomiej, Zieliński Dariusz

Przegląd Elektrotechniczny

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2022

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R. 98, nr 9

67--72

PL

W artkule przedstawiono problem jakim jest wpływ asymetrii prądów fazowych oraz kierunek przepływu energii na prąd jałowy transformatora w konfiguracji uzwojeń gwiazda trójkąt. Zaproponowany sposób rozwiązania problemu oparty jest na równoległym podłączeniu do sieci nN przekształtnika AC/DC z magazynem energii, który posiada możliwość niezależnego sterowania mocą czynną i bierną w każdej z faz. Przeprowadzane badania wykazały słuszność zaproponowanego rozwiązania.

EN

The paper presents the problem of the influence of phase current asymmetry and the direction of energy flow on the idle current of a transformer in star-delta winding configuration. The proposed method of solving the problem is based on the parallel connection to the LV network of an AC/DC converter with energy storage, which has the ability to independently control the active and reactive power in each phase. The conducted tests showed the validity of the proposed solution.

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Control of a Four-wire Hybrid Prosumer Converter for Balancing Utility Grids

Kwaśny Łukasz, Zieliński Dariusz

Power Electronics and Drives

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2021

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Vol. 6 (41)

1--11

EN

The paper presents the project of the power electronic AC/DC converter operating under a multiresonant control algorithm for prosumer applications. This design allows independent control of active and reactive power for any or each phase. Both the converter and its algorithm are based on a three-phase converter of four-wire topology (AC/DC 3p-4w) with a DC bus, which couple the converter to a renewable energy source and energy storage. Further, model and simulation tests were carried out in the Matlab-SIMULINK programming environment. The results obtained indicate that operation with deep unbalances and powers of opposite signs in individual phases results in current variations (oscillations) in the DC line, which is a significant limitation, and it can be concluded that the level of asymmetry should be limited to the level acceptable to the energy storage device.

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An evaluation of the accuracy of inverter sync angle during the grid's disturbances

Jarzyna Wojciech, Zieliński Dariusz, Gopakumar K.

Metrology and Measurement Systems

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2020

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Vol. 27, nr 2

355--371

EN

The grid-tied inverter synchronizes with the network on the basis of the instantaneous voltage phase angle. This angle is computed by the so-called synchronization algorithms. During grid disturbances, it is estimated with a certain accuracy, which varies for different disturbances and depends on the choice of algorithm. The tests presented here determine how to make an optimal selection of the synchronization algorithm. The research methods used are modeling, simulation and analysis of the results obtained. One of the most important outcomes is the determination of the root-mean-square sync error and its dynamics denotation. The research conclusions should be of particular interest to designers of distributed energy systems with a large number of inverter energy sources.