In weak grid

grid-tied converter will face the potential instability oscillation and grid current quality challenges induced by high grid impedance and background harmonic voltages. In view of this

the internal-model-based repetitive controller is first used in this paper to ensure the immunity of converter to the background harmonic voltages. Subsequently

to enhance the weak-grid adaptability of converter

and an active damping strategy based on current error feedback is proposed. In this strategy

the damping component injected into the current reference is derived from the current error

thereby effectively excluding the background harmonic disturbances from current reference. As a result

the stability control can be realized while preserving the original immunity of converter to the background harmonic voltages. Theoretical analysis demonstrates that the proposed active damping strategy not only ensures the stable operation of the converter under high-impedance grid conditions with background harmonics but also achieves high-quality grid-injected current. Finally

the effectiveness of the proposed strategy is verified by both simulation and experimental results.