Nonlinear control strategy insuring contribution of PV generator to voltage and frequency regulation

This paper present a novel control scheme for a grid connected PV generator that contributes to the frequency and voltage regulation of a power system. The PV generator consists of a PV panel connected to a DC/AC converter via a DC-DC boost converter. The frequency regulator controls the boost converter and the voltage regulator controls the DC/AC converter. The proposed frequency regulator includes a frequency control module that changes the reference signal of a power control module when the frequency deviation is significant. An adaptive control scheme is employed to find the frequency control module equation and a nonlinear control scheme is used to find the active power control module equation. A backstepping control design method is employed to obtain the proposed voltage regulator equations. It consists of a module that uses the voltage deviation to generate the reference for a q-axis current controller. A module that maintains the DC-link voltage is also included. A backstepping control design method is also employed to find its equations. The proposed control system is evaluated in simulation. The results reveal that with the proposed control scheme, a PV generator behaves like a conventional synchronous generator when the grid frequency changes significantly.