Journal of the Korean Solar Energy Society (한국태양에너지학회 논문집)

The Korean Solar Energy Society (한국태양에너지학회)
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Compensation of Unbalanced Neutral Voltage for Grid-Connected 3-Phase 3-Level T-type Photovoltaic PCS Using Offset Voltage

오프셋 전압을 이용한 계통 연계형 3상 3레벨 T-type 태양광 PCS의 중성점 전압 불평형 보상

  • Received : 2017.07.31
  • Accepted : 2017.12.14
  • Published : 2017.12.30
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Abstract

The DC link of Grid-Connected 3-Phase 3-Level T-type Photovoltaic PCS (PV-PCS) consists of two series connected capacitors for using their neutral voltage. The mismatch between two capacitor characteristics and transient states happened in load change cause the imbalance of neutral voltage. As a result, PV-PCS performance is degraded and the system becomes unstable. In this paper, a mathematical model for analyzing the imbalance of neutral voltage is derived and a compensation method using offset voltage is proposed, where offset voltage adjusts the applying time of P-type and N-type small vectors. The validity of the proposed methods is verified by simulation and experiment.

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References

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