Phase lag compensation for improving the stability of LCL‑type converters under weak grid condition

LCL-type converters are widely used in the sustainable energy generation system due to their flexible current control strategies and high efficiency. The LCL filter has a resonance peak, which needs to be handled appropriately; otherwise, it causes system instability. Single-loop feedback control strategy is very popular at present; it does not require additional sensors to measure the state variables for active damping. Under weak grid condition, the resonance peak of LCL filter shifts to the left evidently and greatly reduces the stability margin; thus, maintaining the stability of single-loop control is a challenging task. This paper presents an improved grid current feedback (GCF) single-loop control strategy, which is designed to raise the stability margin of system to adapt weak grid condition. Low pass filter controller is used for phase lag compensation. A phase margin design method is proposed to ensure system stability, and the corresponding discrete method in z-domain has been proposed in detail. Experiments performed on a three-phase converter platform are finally presented to verify the effectiveness of the proposed phase lag compensation for GCF control strategy.

Statistics

Show / Hide Statistics

Cumulative Counts from September 30th, 2019
Multiple requests among the same browser session are counted as one view. If you mouse over a chart, the values of data points will be shown.

Cite this article

[IEEE Style]

J. Wang, G. Pan, J. Ouyang, C. Liu, Y. Zhou, G. Fei, "Phase lag compensation for improving the stability of LCL‑type converters under weak grid condition," Journal of Power Electronics, vol. 22, no. 5, pp. 727-738, 2022. DOI: 10.1007/s43236-022-00396-z.

[ACM Style]

Jianfeng Wang, Guobing Pan, Jing Ouyang, Chengyao Liu, Yinghao Zhou, and Gong Fei. 2022. Phase lag compensation for improving the stability of LCL‑type converters under weak grid condition. Journal of Power Electronics, 22, 5, (2022), 727-738. DOI: 10.1007/s43236-022-00396-z.