태양광 인버터의 노치 필터 최적 설계

• Published in: 한국태양에너지학회 논문집 Vol. 39; no. 2; pp. 81 - 92
• Main Authors: 김용래(Kim Yong-Rae), 허철영(Heo Cheol-Young), 이영권(Lee Young-Kwoun), 최익(Choy Ick), 최주엽(Choi Ju-Yeop)
• Format: Journal Article
• Language: Korean
• Published: 한국태양에너지학회 2019
• Subjects: 기타공학; 노치 필터(Notch filter); 120 Hz AC 리플(120 Hz AC ripple); 계통 연계형 인버터(Grid-connected PCS); 120 Hz AC
• ISSN: 1598-6411; 2508-3562
• DOI: 10.7836/kses.2019.39.2.081

When Photovoltaic inverter is connected to grid and used as PVPCS (Photovoltaic Power Conditioning System), 120 Hz AC ripple occurs at the dc-link capacitor voltage. This AC ripple reduces the efficiency of PVPCS and shortens the lifetime of the capacitor. In this paper, we design a notch filter to remove AC ripple. As a result, the AC voltage ripple was removed from the dc link and the THD of the PVPCS output current with the notch filter was lowered. This notch filter is determined by the damping coefficient, the bandwidth coefficient, and the switching frequency. Among these, the switching frequency determines the switching loss and the size of the LC filter, and the PVPCS with the high switching frequency has a greater efficiency loss due to the switching loss than the efficiency improvement by the notch filter. Therefore, it is important to set the optimum switching frequency in the PVPCS with the notch filter applied. In this paper, THD and switching loss of PVPCS output current with notch filter are calculated through simulation, and cost function to calculate optimum switching frequency through data is proposed.