Grid-forming(GFM)converter-based energy storage has the ability to provide frequency and voltage support

which can improve the stability of high-proportion renewable energy power systems.However

due to the secrecy of the technology

the white-box model that depicts the dynamics of GFM converter-based energy storage cannot be directly obtained

which makes it difficult to accurately analyze its response characteristics. Therefore

a closed-loop model is proposed for parameter identification of GFM converter-based energy storage control black box to improve the flexibility of identification scene construction and the accuracy of parameter solving.Firstly

given the lack of adaptability of the existing identification methods to the change of power grid operation state

the source-network interaction characteristics of the converter and the power grid are abstracted into virtual circuits

and the closed-loop model is constructed from the physical essence of power transmission.Secondly

in view of the increase of complexity and the decrease of accuracy caused by the coupling of multiple series control links

a parameter identification method based on virtual steady state operation points was proposed to realize the decoupling of control parameters in different loops.Finally

the effectiveness of the closed-loop model for parameter identification is verified by simulation

and the results show that there is a decoupling condition for the coupling parameters at the virtual steady-state operation point

and the proposed method can significantly reduce the complexity of parameter solving and improve the identification accuracy.