Three-phase single stage photovoltaic inverter with active filtering capabilities

This paper presents a study about the power injection of grid connected photovoltaic plants when there are non-linear loads connected to the point of common coupling. The smart grid scenario suggests that the photovoltaic energy should take care not only about the active power, but also about the reactive power. The study compares the last years criteria of injecting the maximum active power, with the expected tendency of providing reactive power in an active filter way for avoiding currents harmonics in the grid. The topology used is a traditional three-phase inverter controlled by a power balance technique through a synchronous hysteresis band. First of all, a power injection system that do not care about the loads connected into the grid is developed, then the loads are taken into account to improve the grid operation by supplying them. Both configurations are implemented in a prototype to compare the results via experimental tests.