Robust Decoupling Control Based on Linear Extended State Observers for Grid-Forming Inverter

Grid-forming inverters (GFMIs) based on virtual synchronous generators (VSGs) have emerged as a promising solution for providing inertia and enhancing renewable system stability. However, the inherent power coupling caused by the low reactance-to-resistance ratio in low-voltage networks negatively impacts the control performance of VSGs. Commonly used feedforward decoupling methods rely heavily on system parameters. Although these methods can effectively reduce power coupling under nominal systems, their decoupling capability is significantly limited when dynamic variations occur in the system. Therefore, a robust decoupling control strategy based on linear extended state observers (LESOs) is proposed in this paper. The proposed method achieves faster and more efficient decoupling and demonstrates strong robustness in the non-nominal system. Finally, the effectiveness and decoupling ability of the proposed strategy are verified by simulation results.