Small-signal modeling of photovoltaic power generation system and global optimal design for its controller parameters

It is favorable for acquainting with the interactive influence law between solar energy generation system and power grid to research on the transient stability of photovoltaic (PV) generation system. On the basis of overall considering detailed models of important components in PV generation system, a whole system small signal model suitable for transient stability analysis is established and accordingly the small signal stability and low-frequency oscillation characteristics of PV generation system are analyzed. Research results show that the outer voltage loop and the inner active current loop of PV inverter obviously and overall influence on the eigenvalues of the studied system, so the its stability is greatly influenced. Too large values of outer voltage loop's integral coefficient and inner active current loop may affect on the damping of power grid, and even change the damping property of PV generation system. Finally, a global optimal design method of controller parameters, which can enhance system stability, is proposed to provide technical support for the reasonable design of controller parameters.