Transient Stability Analysis and Enhancement Strategy of Hybrid-converter System of Grid-Following and Grid-Forming

In this paper, the transient stability analysis of a hybrid-converter system with paralleled grid-following (GFL) and grid-forming (GFM) control is conducted, followed by the design of a stability-improvement strategy. Firstly, the network model of the hybrid-converter system is formulated, grounded in its control characteristics. Secondly, using the node current law and the equal area criterion (EAC) method, the system's transient stability under grid fault is analyzed, focusing on the influence exerted by the power angle interactions between GFL and GFM converters. Following this, an added control strategy is introduced, aimed at enhancing the transient stability by regulating the power angle difference. At last, simulation outcomes are presented to substantiate the efficacy of the introduced strategy.