Notch correction strategy of LCL-type grid-connected inverters based on GCFAD

Considering the control delay, grid-current-feedback-active-damping(GCFAD) method can ensure the stability of the system through the reasonable design of parameters, but when the grid impedance changes, the system may be unstable because the LCL resonance peak cannot be effectively suppressed. In this paper, a notch correction strategy is proposed. The amplitude drop characteristic of the notch filter is used to effectively suppress the LCL resonance peak in this paper, so as to ensure that the system has sufficient amplitude margin when the grid impedance changes. The robustness of the system is greatly improved to the grid impedance when the GCFAD method is adopted. Finally, the simulation model verifies the effectiveness of the proposed strategy.