A new active filtering technique for grid-connected inverters

This paper presents a new active filtering technique, that is an attractive interfacing for single-phase grid-connected inverter in power distribution systems using renewable energy. The active filtering is obtained by a “filter” full-bridge inverter, characterized by low power and high switching frequency. It is suitably connected by a high frequency transformer and a light passive filter to the main power full-bridge, so as to greatly reduce the harmonic content of the grid current. The implementation of the proposed technique is realized by a single inverter with four legs and two proportional-resonant current controllers.