Parameter Setting Method for Hybrid System with Grid-Following and Grid-Forming

With the widespread use of new energy converters, local grids may exhibit weak grid states, posing challenges to the stable operation of power systems. The article discusses the parameter setting method for hybrid systems with grid-following (GFL) and grid-forming (GFM) converters, aiming to enhance the stability of power systems under weak grid conditions. The paper establishes the state space model of the hybrid system and mathematically models the control strategies for both GFL and GFM systems. The paper discusses in detail the design methods for LC filters, phase-locked loop (PLL), and current loop PI parameters, as well as the parameter setting for grid-forming converters' <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q-v$</tex> control and dual closed-loop voltage and current parameters. Finally, the paper investigates the parameter adjustment methods for hybrid systems, including the impact of converter ratios on system parameter setting, and validates the findings using the MATLAB experimental platform. The study shows that by reasonably adjusting the parameters and ratios of GFL and GFM converters, the oscillation issues under weak grids can be effectively improved, enhancing the system's stability.