Open AccessEffects on oscillation mechanism and design of grid‐voltage feedforward in grid‐tied converter under weak grid
Author(s) -
Wang Guoning,
Du Xiong,
Shi Ying,
Yang Yougeng,
Sun Pengju,
Li Guanghui
Publication year - 2019
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.2018.5232
Subject(s) - feed forward , control theory (sociology) , oscillation (cell signaling) , phase margin , voltage , low frequency oscillation , electrical impedance , phase locked loop , output impedance , engineering , electric power system , computer science , power (physics) , electronic engineering , physics , control engineering , electrical engineering , control (management) , cmos , quantum mechanics , artificial intelligence , amplifier , operational amplifier , biology , jitter , genetics
Grid‐voltage feedforward control is widely used in grid‐tied converters. The reported studies show that the grid‐voltage feedforward may reduce the system stability margin, and may lead to oscillation problem in renewable power generation system. This study revisits the effect of voltage feedforward control on system stability and especially focuses on low frequency oscillation with impedance‐based method. The low frequency oscillation usually happens in industry around 100 Hz and shows frequency coupling characteristics. A converter equivalent impedance which includes the effects of voltage feedforward and also covers the frequency coupling introduced by phase locked loop (PLL) is established. Based on the built impedance, the effect on oscillation mechanism with voltage feedforward and PLL is revealed. The results show that the voltage feedforward could increase the system stability margin and may be employed to improve the system stability. Then how to design an optimal proportional voltage feedforward control is demonstrated. Experimental results verify the theoretical analysis and the design of the proportional grid‐voltage feedforward control.