A Complex-Coefficient Voltage Control for Virtual Synchronous Generators for Dynamic Enhancement and Power-Voltage Decoupling

TL;DR

This paper proposes a novel complex-coefficient voltage control strategy for virtual synchronous generators (VSGs) to improve stability, dynamic response, and decouple power-voltage interactions in inverter-based power systems.

Contribution

It introduces a second-order control dynamics analysis and a comprehensive controller design with pole placement and transient correction, enhancing VSG performance in decarbonized grids.

Findings

Improved voltage stability and dynamic response demonstrated in simulations.

Reduced control interaction issues and transient power overshoot.

Validated effectiveness through experiments and simulations.

Abstract

As electric power systems evolve towards decarbonization, the transition to inverter-based resources (IBRs) presents challenges to grid stability, necessitating innovative control solutions. Virtual synchronous generator (VSG) emerges as a prominent solution. However, conventional VSGs are prone to instability in strong grids, slow voltage regulation, and coupled power-voltage response. To address these issues, this paper introduces an advanced VSG control strategy. A novel analysis of the VSG control dynamics is presented through a second-order closed-loop complex single-input single-output system, employing a vectorized geometrical pole analysis technique for enhanced voltage stability and dynamics. The proposed comprehensive controller design mitigates issues related to control interacted subsynchronous resonance and $dq \leftrightarrow 3\phi$ transformation-induced voltage-coupled power transients, achieving improved system robustness and simplified control tuning. Key contributions include a two-fold design: optimized voltage transition characteristics through direct pole placement and transient power overshoot correction via a compensator. Validated by simulation and experiments, the findings offer a pragmatic solution for integrating VSG technology into decarbonizing power systems, ensuring reliability and efficiency.