Small-Signal Stability Analysis of Synthetic Inertia-Based Photovoltaic Generators

Frequency stability is a consequential issue in power systems dominated by inverter—based generators. To mitigate potential frequency stability problems, inertia emulation concept must be employed in the control of interfaced inverters. This study presents the small—signal state—space realization of a double—stage photovoltaic (PV) generator augmented with synthetic inertia emulator (SIE). The inertia power is provided by the inverter dc—link ultracapacitor. Synchronization of the generator with the host grid is performed using a fast but accurate frequency—locked loop (FLL). The impact of synthetic inertia loop and FLL bandwidth on the PV generator stability is scrutinized as the main contribution. The accuracy of theoretical studies and proper operation of the PV generator are examined through simulations in MATLAB/Simulink.