Active damping strategy for two‑stage grid‑connected converters with PV output fluctuations under weak grid conditions

Chengbi Zeng; Yuxiang Zhao; Hong Miao; Jihao Su

Active damping strategy for two‑stage grid‑connected converters with PV output fluctuations under weak grid conditions

Vol. 25, No. 7, pp. 1272-1283, Jul. 2025

10.1007/s43236-024-00973-4

Abstract

Aiming at solving the problem of insufficient damping and resonance for two-stage PV converter systems with LCL filters under weak grid conditions, a novel bilateral active damping control strategy based on the feedbacks of both DC capacitor voltage and AC filter capacitor current is proposed. The capacitor current of the LCL filter is used as feedback to realize the zero pole cancellation of the transfer function, reduce the order of system equivalent model, track the migration of the resonant point, and suppress the resonant peak. A state observer is used to measure the filtered capacitor current instead of a sensor to reduce the system cost. Furthermore, the capacitor voltage of the inverter DC side is used as feedback to the inverter voltage control loop. Therefore, the fluctuation of the inverter DC voltage is suppressed and the resonant risk can be reduced when the PV output varies. The resonant characteristics of a PV two-stage LCL converter system with the proposed damping strategy are analyzed under different weak grid situation. Theory analyses, simulations, and experiment results all verify that when compared to the traditional unilateral damping strategy of capacitive current feedback, the proposed bilateral active damping strategy has a better damping effect.

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]

C. Zeng, Y. Zhao, H. Miao, J. Su, "Active damping strategy for two‑stage grid‑connected converters with PV output fluctuations under weak grid conditions," Journal of Power Electronics, vol. 25, no. 7, pp. 1272-1283, 2025. DOI: 10.1007/s43236-024-00973-4.

[ACM Style]

Chengbi Zeng, Yuxiang Zhao, Hong Miao, and Jihao Su. 2025. Active damping strategy for two‑stage grid‑connected converters with PV output fluctuations under weak grid conditions. Journal of Power Electronics, 25, 7, (2025), 1272-1283. DOI: 10.1007/s43236-024-00973-4.