SOGI-Enhanced Virtual Flux Oriented Deadbeat Control for Grid-Forming Converters

The increasing penetration of inverter-based renewable energy resources (IBRs) challenges the stability of modern power systems, particularly due to reduced inertia and weakened voltage and frequency regulation. Grid-forming inverters (GFMIs) have become essential for restoring these capabilities. Among various control strategies, virtual flux-oriented control (VFOC) introduces an alternative control framework by utilizing virtual flux as the central control variable. However, conventional implementations based on proportional-integral (PI) controllers and fixed-frequency low-pass filters (LPFs) suffer from steady-state errors and limited adaptability to frequency deviations. To address these limitations, this paper proposes an improved VFOC strategy that integrates a Second-Order Generalized Integrator (SOGI) for frequency-adaptive flux estimation and a deadbeat controller for fast, parameter-free voltage reference generation. The proposed method enhances dynamic response, improves robustness across operating conditions, and maintains accurate droop characteristics. Simulation results validate its effectiveness and demonstrate better performance compared to conventional PI-based VFOC methods.