Control Strategy of LCL Grid-Connected Inverter Based on Hybrid Damping in Weak Grid

Due to the influence of grid impedance, excessive damping occurs in the grid connected inverter system, and the system will be unstable. In this paper, a hybrid damping control strategy under weak grid conditions is studied for increasing response speed of inverter system, and decreasing harmonic distortion. The hybrid damping control strategy uses capacitor current feedback and capacitor series resistance as damping to suppress the system resonance. The simulation results showed that the control strategy can reduce the influence of the grid impedance on the grid-connected system.