DC microgrid and AC grid are connected through a grid connected converter (GCC). As the strength of the AC grid decreases

GCC control parameters designed for an ideal grid may induce DC bus instability. To address this issue

a control parameter optimization design method for GCC considering the influence of grid strength is proposed. Firstly

a GCC DC side impedance model considering the impact of grid strength on DC bus stability is developed. A quantitative analysis is performed to evaluate the effects of GCC control parameters on system dominant poles and their sensitivity to DC-side stability under varying grid strengths

revealing significant differences in the impact of different parameters on stability when grid strength changes. On this basis

a graphical optimization design method for high-sensitivity parameters that considers both dynamic and steady-state characteristics as well as DC side stability under low grid strength is proposed

and a parameter design flowchart is provided. Finally

the correctness of the impedance model

stability analysis

and control parameter optimization design are verified through simulation and experiments. Research results demonstrate that the proposed parameter design method can be adopted to effectively enhance DC bus stability under low grid strength while maintaining good dynamic and steady-state characteristics of the GCC

providing guidance for GCC design under different power grid strengths.