Grid-Voltage-Feedback Active Damping With Lead Compensation for LCL-Type Inverter Connected to Weak Grid

Abstract

To improve the robustness and stability of the LCL inverter connected to weak grid, this paper proposes a novel active damping based on voltage of point common coupling ( $\text{v}_{pcc}$ ) feedback. A phase lead compensator is proposed in the $\text{v}_{pcc}$ feedback loop to compensate system phase margin (PM). Theoretical analysis of the effectiveness, detailed parameter setting, stability analysis for proposed active damping adopting lead compensator, named as LC AD, are all described. Simulation and experiment results show that comparing to conventional high pass filter (HPF) AD, the proposed LC AD provides more effective damping effect for the LCL inverter adopting quasi-proportional resonant (QPR) controller under weak grid.

Keywords

• Weak grid
• LCL filter
• grid-connected inverter
• active damping