Modeling and Small-Signal Stability Analysis of Grid-Following Photovoltaic System

Accurate modeling of grid-forming photovoltaic (PV) power generation systems is imperative to characterize the dynamic interactions among PV arrays, power inverters, and grid interfaces. Existing modeling studies of grid-forming PV systems largely neglect PV module dynamics and phase-locked loop (PLL) interactions, failing to capture the impact of irradiance, temperature, and grid strength variations on system dynamic stability. This paper explicitly integrate PV array dynamics and nonlinear PLL behavior into a full-order state space small-signal model. First, a critical synthesis of limitations in existing photovoltaic modeling literature is conducted. Subsequently, a state-space small-signal model is developed. To validate the accuracy of the small-signal model, an electromagnetic transient simulation model is implemented in MATLAB/SIMULINK, with results cross-verified against theoretical predictions. Finally, eigenvalue root locus analysis is conducted on the state-space model to evaluate the stability impacts of control parameters in grid-following PV generation system.