Large-Signal Synchronization Stability Analysis of Electronic Converters Based on Hybrid Grid-Forming and Grid-Following Control Strategy

Grid-forming control has become the dominant control strategy for renewable energy grid integration, due to its capabilities in providing inertia and voltage support. However, while GFM control is susceptible to small-signal stability issues under strong grid conditions, it is also prone to trigger current limiting during large disturbance transients, which make the converter fail to operate under a normal grid-forming control mode. By integrating the synchronization mechanisms of grid-forming and grid-following controls, hybrid grid-forming and grid-following control combines the advantages of both, making it a growing research focus. The grid-connection topology and typical control strategy of hybrid grid-forming and grid-following control are given first in this paper. Subsequently, a time-domain model for analyzing the large-signal synchronization stability of hybrid grid-forming and grid-following control is established. Based on this model and the phase portrait analytical method, the key system and control parameters influencing the large-signal synchronization stability characteristics are investigated. Finally, a grid-connected power electronic converter model based on hybrid grid-forming and grid-following control is developed on the PSCAD/EMTDC simulation platform, and the time-domain simulations are conducted to validate the aforementioned analysis.