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Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
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A High-efficiency Single-phase Photovoltaic Inverter for High-voltage Photovoltaic Panels

고전압 태양광 패널용 고효율 단상 태양광 인버터

  • Hyung-Min, Ryu (Dept. of Electrical Engineering, Dong-eui University)
  • Received : 2022.11.11
  • Accepted : 2022.12.13
  • Published : 2022.12.31
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Abstract

For DC-AC power conversion from a high-voltage photovoltaic panel to a single-phase grid, the two-stage transformerless inverter with a buck-boost converter followed by a full-bridge inverter is widely used. To avoid an excessive leakage current due to the large parasitic capacitance of the photovoltaic panel, the full-bridge inverter can only adopt the bipolar PWM which results in much higher power loss compared to the unipolar PWM. In order to overcome such a poor efficiency, this paper proposes a new topology in which an IGBT and a diode for circuit isolation are added to the buck-boost converter. The proposed circuit isolation method allows the unipolar PWM in the full-bridge inverter without any increase in the leakage current so that the overall efficiency can be improved. The validity of the proposed solution is verified by computer simulation and power loss calculation.

고전압 태양광 패널에서 단상 계통으로의 직류-교류 전력 변환을 위해 벅부스트 컨버터에 풀브리지 인버터를 종속적으로 연결하는 두 단계의 무변압기 인버터가 주로 사용된다. 태양광 패널의 큰 기생 커패시턴스에 기인하는 과도한 누설 전류를 피하기 위해 풀브리지 인버터는 단극성 PWM에 비해 훨씬 더 많은 전력 손실을 초래하는 양극성 PWM으로만 스위칭할 수 있다. 그런 낮은 효율을 개선하기 위해 본 논문은 벅부스트 컨버터에 회로 절연을 위한 IGBT와 다이오드를 하나씩 추가한 새로운 토폴로지를 제안한다. 제안된 회로 절연 방식은 누설 전류를 증가시키지 않으면서 풀브리지 인버터에서 단극성 PWM을 가능케 함으로써 전체 효율을 개선한다. 제안된 방법의 타당성은 컴퓨터 시뮬레이션과 전력 손실 계산을 통해 검증한다.

Keywords

Acknowledgement

This work was supported by Dong-eui University Foundation Grant(2018).

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