Enhanced Decentralized Virtual Oscillator Control for Dynamic Stability of Paralleled Inverters Across Various Grid Strengths

Grid-forming inverters (GFMs) allow power electronics converters (PECs) to support the grid by regulating the output frequency and voltage of the PEC, while grid follow control (GFL) is widely used, as it can be synchronized with the grid through a phase-locked loop. Indeed, this paper proposes a sophisticated approach, namely enhanced virtual oscillator control (EVOC), which incorporates the proportional derivative to the traditional virtual oscillator control (VOC) to eliminate the variation in the output voltage of the PEC and enhance PEC dynamic stability with various grid strengths. In practice, the effect of grid strengths on virtual oscillator control (VOC), GFL, and virtual synchronous generators (VSG) dynamic stability is compared. The proposed EVOC offers additional degrees of freedom to fine-tune the VOC real-time performance for MG stability improvement. In order to show the effectiveness of the proposed controller, numerical simulations validate that the EVOC algorithm surpasses traditional VOC in adaptability, stability, and reliability across a spectrum of grid conditions, marked by a significant improvement in phase margin and accelerated dynamic response. A comprehensive comparison with other VOC types has been employed to show the effectiveness of the proposed control by providing the optimal dynamic response. Furthermore, the proposed approach is validation experimentally.