Inverter-Side Current Feedback Active Damping Based on Phase-Lead Compensation for Grid-Connected Inverter

To suppress the resonance in LCL-type grid-connected inverter (GCI), various active damping (AD) methods have been developed. In this article, an inverter-side current feedback active damping (ICFB-AD) strategy with phase-lead compensation is proposed, which achieves both resonance attenuation and accurate current control. A second-order unstable phase-lead filter is introduced in series with the ICFB loop to enhance the stability and robustness of the GCI. Design guidelines for the second-order unstable PLF are also presented. The proposed system ensures stability across a wide range of LCL resonance frequencies and exhibits strong robustness against variations in the filter inductance and grid impedance. Finally, the effectiveness of the proposed ICFB-AD strategy, along with its z-domain design methodology, is validated by experimental results.