Yazar "Uzunoglu, C. P." seçeneğine göre listele

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    Amplitude and frequency detection of power system signals with chaotic distortions using independent component analysis
    (ELSEVIER SCIENCE SA, 2014) Ugur, M.; Cekli, S.; Uzunoglu, C. P.
    In this paper independent component analysis (ICA) method for amplitude and frequency estimation of highly distorted power system signals is presented. In a power system the accuracy of amplitude and frequency detection is strictly related to distortion strength of the system signal. Distorted system signal may contain chaotic (ferroresonance) and non-chaotic (white, pulse, harmonic etc.) noise. In this study, chaotic distortions are used to contaminate system signal, which is the worst case scenario for a power system. The proposed method is employed to eliminate the noise and hence to improve the efficiency of the estimation. To simulate chaotic distortions Duffing Oscillator solutions are used. Computer simulations have been carried out for the performance analysis of the proposed method and the comparison of the results of the proposed method with the conventional filters are presented. (C) 2013 Elsevier B.V. All rights reserved.
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    Wavelet analysis of a memristor emulated model proposed for compact fluorescent lamp operated systems
    (ELSEVIER SCIENCE SA, 2018) Babacan, Y.; Uzunoglu, C. P.; Cekli, S.; Kacar, F.; Ugur, M.
    Compact fluorescent lamps (CFLs) are widely employed in lighting systems thanks to their energy efficient characteristics. In contrast to incandescent lamps, CFLs have highly non-linear current-voltage characteristics and exhibit harmonic distortions during their operation. Although nonlinearity and accelerated harmonic effects may cause disturbance in power networks, CFLs are frequently preferred due to their low energy consumption. In this study a test set-up is operated for investigating non-linear characteristics of commercially available CFLs. During these tests non-linear current and voltage waveforms of CFLs are analyzed via oscilloscope and compared with the proposed memristor emulator circuit output waveforms. The non-linear characteristics of CFLs are accurately modelled by proposed memristor emulator circuit, which has a tunable threshold property. To obtain proper comparison wavelet analysis is conducted for current waveforms of CFLs and memristor emulator circuit. The wavelet analysis is an efficient tool for processing non-linear signals, which are prone to display high frequency distortions. In addition to wavelet analysis, the Fourier Transform (FFT) characteristics and total harmonic distortion (THD) levels are also analyzed for correlation of CFLs and proposed memristor. (C) 2018 Elsevier B.V. All rights reserved.