A Study of Multi-Band Distribution and Main Factors Based on Impedance Model of Grid-Following and Grid-Forming Converters

With the shift from traditional thermal power generation to renewable energy generation modes, the power equipment used in traditional generation cannot be directly applied to renewable energy systems. Currently, power electronic converters are commonly controlled using GFL (Grid-Following) converters and GFM (Grid-Forming) converters. However, the integration of renewable energy increases the potential for system instability, leading to significant oscillations and instability in power supply. To fully leverage the advantages of both types of inverters and ensure system stability, this paper develops an impedance model for the coexistence of GFL and GFM converters. Additionally, a Conventional Power System Stabilizer (PSS) is incorporated to suppress frequency oscillations and maintain system stability. Firstly, mathematical impedance modeling is conducted for GFL and GFM converters. Moreover, stability analysis is performed on the stability control device for the coexistence of GFL and GFM converters to ensure effective suppression of frequency oscillations. Finally, simulations are carried out to assess the power output of the designed impedance model for GFL and GFM converters under different frequency ranges. By developing mathematical models and performing simulations of the device, the stability of the device during operation is ensured.