6. Black-box imedence identification and stability analysis of grid connected inverter under multiple operating points
Shibei Li, Mohammad Hasn Ravanji, Behrooz Bahrani - Department of Electrical and Computer Systems Engineering Monash University, Melbourne, Australia
Black-box imedence identification and stability analysis of grid connected inverter under multiple operating points
- Inverter-based resources (IBRs) support high renewable energy penetration, but also introduce new challenges to power system, such as low-frequency oscillations.
- Small-signal analysis enables stability assessment of grid-connected inverter system around steady state operating points.
- Small-signal models can be derived using component connection methods (CCM), but the reliance on internal IBR details motivates black-box approaches.
- To enable black-box modeling, frequency domain impedance is identified via frequency scan, with polynomial representations parameterized by multiple operating points.
- The identified impedance is synthesized into a state-space model (SSM) via vector fitting and combined with a single machine infinite bus (SMIB) grid model to form the overall system SSM.
- Eigenvalue-based analysis is conducted under varying short-circuit ratios (SCRs), and validated through time-domain simulations.