• Title/Summary/Keyword: Virtual resister

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Stability Analysis of Current Control based on Virtual Resistor for Single-Phase Grid Converters with LLCL Input Filters (LLCL 입력필터를 갖는 단상 그리드 컨버터의 가상 저항에 따른 전류제어 안정도 해석)

  • Bae, Cheol-Ju;Lee, Dong-Choon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.5
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    • pp.404-410
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    • 2016
  • To avoid the stability issues of LLCL filters, passive or active damping methods to eliminate the resonance phenomena are required. In this paper, system stability of a current control is analyzed when the active damping scheme based on the virtual resister is utilized in single-phase grid converter systems with LLCL input filters. The control performance according to the parameters of the virtual resistance is investigated. The validity of stability analysis was verified by simulation and experimental results.

Development of Novel Algorithm for Anti-Islanding of Grid-Connected PV Inverter (계통연계형 태양광 인버터의 단독운전 방지를 위한 새로운 알고리즘 개발)

  • Choi, Jung-Sik;Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.10
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    • pp.76-86
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    • 2011
  • This paper proposes novel algorithm for anti-islanding of grid-connected photovoltaic(PV) inverter. The islanding of PV systems can cause a variety of problems such as deterioration in power quality and electric shock. To prevent islanding, many anti-islanding methods are researched. Typical methods of anti-islanding are active frequency drift(AFD) and active frequency drift positive feedback(AFDPF). However, the AFD has problem that widely exists non diction zone(NDZ). The AFDPF is a method that improves the AFD method and is detected islanding by changing the chopping fraction(cf). However, The AFDPF does not detect when cf is very small and does not satisfy the IEEE Std. 929-2000 when cf is very big. Therefore, this paper proposes novel anti-islanding method that is simple to implement using virtual resister. The anti-islanding method proposed in this paper is compared with conventional method. The validity of this paper is proved using this result.