Design of feedback laws for dc-to-ac conversion in photovoltaic systems

One-phase dc-ac stand-alone conversion for a photovoltaic standard panel is analyzed in this paper. A modular structure consisting of the cascade connection of a voltage step-up dc-to-dc switching converter with galvanic isolation and a buck converter-based inverter stage is proposed. Different feedback laws for the inverter stage are investigated to guarantee output voltage regulation. A comparative analysis of the modular structure performance under voltage-mode control, current-mode control and optimal control based on linear quadratic regulator (LQR) approach is studied by means of simulation.