Active damping-based control for grid-connected LCL-filtered inverter with capacitor voltage inertial feedback

The LCL filter is widely applied in grid-connected inverter due to its good attenuation to high order harmonics. However, it is easily oscillated and causes system instability. This paper proposes a novel active damping (AD) method. It adopts capacitor voltage inertial feedback to inhibit resonance without increasing sensors in comparison with the typical AD methods. The grid voltage full feedforward function, which consists of three parts, is deduced on the basis of the proposed method. Further study of the function indicates the proposed method can suppress the injected current distortion caused by grid background harmonics within 13 times markedly even though without the grid voltage feedforward. Simulation results verify the effectiveness of the proposed method.