Grid-forming converters with frequency & voltage active support and distributed cooperative control for active and reactive power sharing

Abstract

In islanded AC microgrids, grid-forming converters (GFCs) often employ virtual synchronous generators (VSGs) with virtual inertia and droop characteristics. However, this approach can lead to deviations in frequency and voltage from their rated values, affecting power quality and potentially compromising the security of the power supply. In addition, the power allocation is influenced by line impedance, and due to the uneven parameters among GFCs, it cannot be fully evenly shared. This paper presents a distributed control strategy for GFC that integrates frequency-voltage active support with power coordination control. This distributed strategy is implemented using multi-agent consensus theory, which ensures that the frequency and voltage of the GFCs remain at their rated values while accurately distributing active and reactive power across each GFC. It addresses the limitations of VSG control while maintaining a lower communication burden. Furthermore, several Hardware-in-the-Loop (HIL) experiments were conducted across multiple cases, validating the effectiveness of the proposed strategy and further enhancing it through cross-case analysis.