Open AccessFeedforward phase compensation method of LCL grid‐connected inverter based on all‐pass filter in weak grid
Author(s) -
Xue Tongyu,
Sun Pengju,
Xu Zezhong,
Luo Quanming
Publication year - 2020
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2020.0897
Subject(s) - feed forward , control theory (sociology) , inverter , harmonics , grid , robustness (evolution) , computer science , capacitor , control system , electronic engineering , voltage , engineering , control engineering , control (management) , electrical engineering , mathematics , geometry , artificial intelligence , biochemistry , chemistry , gene
Inverter‐side current feedback control (ICFC) has been extensively adopted in distributed generation systems because of its simple implementation and better consistency with actual operating conditions. At the same time, when there are a large number of background harmonics in the grid, capacitor voltage feedforward (CVF) is usually added to the system for its suppression. This method could make the system keep the first‐order characteristics under the analogue control. However, under digital control, due to the digital control delay, a reverse resonance peak will be generated in the loop gain, which makes the system unstable in the weak grid. In order to solve the aforementioned problems, this study proposes a feedforward phase compensation method of LCL grid‐connected inverter based on the all‐pass filter (AF). By introducing AF into the CVF channel, the phase lag in the range of reverse resonance peak frequency is compensated, so as to enhance the robustness of the system in the weak grid. At the same time, this study gives the detailed design process of the proposed method. Experimental results on a 3‐kW prototype are provided, and the effectiveness of the proposed control method is verified..