Browsing by Author "Sevilmiş, Fehmi"

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Citation - WoS: 9
Citation - Scopus: 11
Enhanced Control Method for Voltage Regulation of Dstatcom Based Seig
(Elsevier, 2022) Özer, Ali Sait; Sevilmiş, Fehmi; Karaca, Hulusi; Arabacı, Hayri
Self-excited induction generator (SEIG)-based wind energy conversion systems (WECS) are very popular for feeding standalone loads in remote areas where there is no grid. SEIG needs adjustable reactive power to regulate terminal voltage and frequency. Usually, a combination of a distributed static compensator (DSTATCOM) and a fixed capacitor bank is used to meet this reactive power demand. DSTATCOM is the most suitable option for power quality compensation. The performance of DSTATCOM depends on its control algorithm that generates the proper switching signals for voltage source inverter (VSI). Many control algorithms have been proposed for DSTATCOM in the literature. Among them, the most frequently used algorithms are synchronous reference frame (SRF), instantaneous reactive power (IRP), and current synchronous detection (CSD) algorithms. An effective control algorithm must accurately estimate the amplitude of the terminal voltage without being affected by harmonics, DC-offset, and frequency variation. For this purpose, an enhanced phase locked loop (EPLL)-based CSD control algorithm is proposed to estimate the amplitudes of individual phase voltages, and to filter SEIG voltages in case of harmonics, DC offset, and frequency variation. The proposed algorithm has been tested under linear and nonlinear load conditions. The obtained results clearly demonstrate the effectiveness of the proposed EPLL-based CSD control algorithm. (C) 2022 The Author(s). Published by Elsevier Ltd.
Performance Comparison of Phase Locked Loop Methods for Grid Interactive Inverters
(Konya Technical University, 2019) Sevilmiş, Fehmi; Karaca, Hulusi
In grid interactive power converter applications, phase locked loop (PLL) methods are very important to realize grid synchronization. The performance of PLL which is used should be affected by adverse conditions such as voltage unbalance, harmonics, frequency and phase changes. Furthermore, in these adverse conditions, the phase angle of grid voltages and positive sequence component of grid voltages in fundamental grid frequency are needed to determine quickly and accurately. Otherwise, synchronization errors occur between the grid interactive inverter and the grid.In this paper, different PLL methods are simulated under MATLAB/Simulink. The performances of the PLL methods are comparatively presented under three different conditions such as unbalanced, harmonics and variable frequency grid. It has also put forward the positive and negative aspects of the PLL methods based on the obtained results.