Novel LCL filter for non-isolated photovoltaic inverters with CM current trapping capability for weak grids

Abstract

© 2018 IEEE. In this work, a novel LCL filter topology for non-isolated Photovoltaic (PV) applications is developed. This topology has the ability to trap the High-Frequency (HF) Common Mode (CM) current inside the PV inverter. Consequently, suppressing the ground leakage current. Furthermore, the proposed solution is immune to ground leakage current resonance issues (i.e. effective for applications where the utility grid is characterized as a weak grid). Moreover, the theoretical analyses were validated on a 10 kW grid-connected PV system. The results demonstrated that at resonance conditions, the proposed system reduced the leakage current root-mean-square (RMS) value from 1 A to 25 mA. Thus, satisfying the VDE standard's leakage current limit.