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A modulation method for leakage current reduction in a three-phase grid-tie quasi-Z-source inverter

Noroozi, N ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1109/TPEL.2018.2868799
  3. Publisher: Institute of Electrical and Electronics Engineers Inc , 2018
  4. Abstract:
  5. The leakage current originated from the fluctuations of the common-mode voltage (CMV) is an issue in a transformerless grid-connected photovoltaic (PV) system. In this paper, a modified space vector modulation based on the Fourier transform analysis is proposed to reduce the leakage current in a three-phase quasi-Z-source inverter (qZSI). The CMV harmonic content in a qZSI contains low and high-frequency harmonics which cause safety and EMI problems respectively. By implementing the proposed modulation in a three-phase qZSI, the low-frequency harmonics of the CMV are mainly reduced. The distribution of the high-frequency harmonics is also modified in a way they can be simply filtered. Passive filtering in a qZSI using other modulation techniques is less effective than using this method. Applying the proposed modulation in the presence of a high-frequency inductive-capacitive filter results in the strong suppression of both high and low-frequency harmonics (more than 90% in the investigated case). A reduced-voltage prototype is designed to evaluate the modulation method. The experimental results from this prototype verify the accuracy of the proposed technique. IEEE
  6. Keywords:
  7. Common-mode voltage ; Fourier transform ; Harmonic analysis ; Inverters ; Leakage current ; Modulation ; Power harmonic filters ; quasi-Z-Source inverter ; Electric inverters ; Fourier series ; Fourier transforms ; Leakage currents ; Passive filters ; Switches ; Vector spaces ; Common mode voltage ; Fourier transform analysis ; Grid-connected photovoltaic system ; High-frequency harmonics ; Leakage current reduction ; Low and high frequencies ; Z-source inverter
  8. Source: IEEE Transactions on Power Electronics ; 2018 ; 08858993 (ISSN)
  9. URL: https://ieeexplore.ieee.org/document/8454479