Current control for inverter-interfaced grid-connected photovoltaic generator

A theoretical analysis, control and a simulation of a grid connected photovoltaic system using an output LCL filter is detailed in this paper. In order to reduce the complexity of the system, a linear voltage and current controllers have been developed for a three phase grid connected inverter. Those controllers simultaneously regulate the dc link voltage (the photovoltaic power is delivered to the grid) and the current injected to the grid (to operate at unity power factor). The adopting of an LCL filter configuration allows to use reduced values of inductances and to reduce the switching frequency emitted in the grid. The main goal is to ensure a reduction of the switching frequency which disturbs the local load and equipment. The simulation results show the control performance and the dynamic behavior of the inverter-LCL-grid combination.