Magnetic integration of an LCL filter for the single-phase grid-connected inverter

Abstract

The LCL filter is widely used in grid-connected inverters due to its outstanding performance of attenuating the switching frequency current harmonics. An LCL filter has two individual inductors. Numbers of magnetic cores are required, and large volume has to be reserved for these two inductors. In order to reduce the core volume, magnetic integration of these two inductors is introduced in this paper. Since the attenuating ability of the LCL filter would be weakened by the coupling between the two inductors, decoupled magnetic integration is chosen consequently. Though the reluctance of the common core can hardly be zero, the decoupled magnetic integration scheme is still attractive. A 6-kW prototype is built in the lab, and the experimental results validate the effectiveness of the proposed magnetic integration scheme.