Voltage Stability Mechanism of Grid-Connected Permanent Magnet Synchronous Generator Under Large Grid-Side Disturbances

As a mainstream new energy generation technology, elucidating the grid-connected voltage stability mechanisms of permanent magnet synchronous generator (PMSG) is critical for ensuring stable integration of high-penetration renewable energy. Existing research on the voltage stability of grid-connected PMSG systems is confined to single-fault scenarios, failing to adequately account for the impacts of other significant internal grid disturbances, such as direct current blockings and increased renewable energy penetration. Moreover, the traditionally used simplified grid model with a voltage source in series with an impedance is overly idealized, making it difficult to comprehensively reveal the transient stability mechanisms of grid-connected PMSG systems under complex multi-disturbance conditions. To address this issue, this paper proposes a numerical analysis method to investigate the grid stability mechanisms of PMSG systems under various grid disturbance scenarios. First, an electromagnetic transient simulation model of the grid-connected PMSG system is established. Next, key parameters influencing the system’s voltage stability are identified using the global sensitivity Sobol method. Subsequently, a transient voltage stability assessment index and a method for revealing the grid stability patterns of PMSG systems are presented. Finally, the PMSG system is integrated into the CSEE standard test system on the CloudPSS platform for validation and analysis. The results demonstrate that the proposed method effectively reveals voltage stability mechanisms considering various internal grid disturbances, and the mechanistic characteristics it reveals differ significantly from conclusions drawn using a simplified grid model.