| Title |
A Novel Grid-Forming Converter Control Method for Active Power Ripple Reduction Under Unbalanced Grid Conditions |
| Authors |
Yong-Kyo Seo ; Chi-Hwan Bae ; Hak-Soo Kim ; Jung-Hyun Lee ; Eui-Cheol Nho |
| DOI |
https://doi.org/10.6113/TKPE.2026.31.2.172 |
| ISSN |
1229-2214(pISSN), 2288-6281(eISSN) |
| Keywords |
Grid-forming (GFM); Inverter-based resource (IBR); Negative-sequence; Weak grid |
| Abstract |
Grid-forming (GFM) converters established via stable voltage references play a critical role in weak grids and microgrids. Unbalanced grid conditions may cause active power ripple and frequency variations, and when improperly mitigated, system stability can be compromised. Excessive rippling induces DC link voltage oscillations, degrading inverter performance and potentially threatening overall grid stability. Most ripple reduction methods have been developed for grid-following inverters via phase-locked loops, which cannot be applied directly to GFM converters. The negative-sequence current control-based method has also been developed, but it requires substantial sequence extraction processing and extra current reference calculations, with limited validation in weak-grid environments. This study proposes a simplified control strategy to reduce the active power ripple in GFM converters by avoiding negative-sequence current control and minimizing sequence extraction. The performance of the proposed method, which was validated via hardware-in-the-loop experiments, is robust under weak and unbalanced grid conditions. |