A Model-Free Predictive Control Strategy for dVOC Converter Under Unbalanced Grid Voltages

The dispatchable virtual oscillator control (dVOC) is a fast-responding grid-forming method offering time-domain synchronization and grid support. However, grid unbalanced voltages drop cause current distortion and power fluctuations in dVOC controlled systems, degrading power quality. To solve this, this paper proposes an improved model-free predictive current comprehensive control for dVOC controlled converters. By analyzing the relationships among unbalanced voltages, current and power, a comprehensive control function is proposed to find the optimal negative sequence current reference. The model-free predictive control method is then used to achieve the objectives of grid current balance and suppression of instantaneous power fluctuations. Simulation results verify the effectiveness of the proposed control strategy.