Frequency Response Modeling of Photovoltaic System with Physical Significance

The unclear frequency response process and mechanism of existing photovoltaic (PV) systems have limited the optimization and stability improvement of power systems. Based on a full-order PV system model, this paper analyzes its dynamic characteristics and time-scale structure to identify the dominant participating links in the frequency response dynamics of PV system, while ignoring the fast dynamic links. By using the nonlinear differential equations and state-space linearization model of the PV system, a second-order frequency response model of the PV system is gradually derived, clarifying its mechanism. Full-order, second-order, and first-order PV system are built in MATLAB/Simulink for simulation verification, which shows that the model meets both "high precision" and "low order".