Dynamic Relative Gain Array -based Power Coupling Analysis for Grid-Forming Convertor

The increasing incorporation of renewable energy sources into the power grid has led to a reduction in the capacity of conventional support sources, necessitating the deployment of Grid-Forming (GFM) converters. These converters are crucial for providing essential inertia and damping to the power system, thereby enhancing its stability and reliability. However, in scenarios where the power angle of the GFM's grid-connected equivalent impedance undergoes significant fluctuations, the independent control of the active power loop (APL) and reactive power loop (RPL) in GFM can result in power coupling. This coupling effect can negatively impact the GFM's support capabilities. In response to this challenge, this study develops a small-signal model of GFM based on its main circuit and control system architecture. The dynamic operation of GFM is analyzed to investigate the power coupling mechanism, with the integration of the dynamic relative gain matrix. The theoretical analysis of power coupling is validated for its rationality and accuracy through Matlab/Simulink simulations, providing insights into the GFM's performance under varying power angle conditions.