Determining the accurate fault control parameters is the foundation for analyzing and calculating the fault characteristics and protection configuration of grid-forming (GFM) renewable energy. However

there exists the coupling relationship between power outer loop and voltage and current inner loop in GFM fault control loops

resulting in inaccurate parameter values through unified identification. To address this issue

this paper proposes a stepwise parameter identification method based on time-sequence decoupling. This method identifies the power outer-loop in stages based on the control loop response time

and separately identifies the low voltage ride through control and voltage and current inner loop based on sensitivity analysis and parameter correlation analysis. Additionally

a virtual impedance reactive power equation is introduced to derive a virtual internal potential calculation formula independent of measurements. Intelligent algorithms are used to fit the output waveform

achieving identification of the power outer loop and the voltage/current inner loops. A semi-physical hardware in the loop testing system is built based on the RTDS (Real Time Digital Simulator) real-time simulation platform

demonstrating the effectiveness of the proposed parameter identification method Furthermore

the feasibility of the method is validated by using recorded waveform data from a GFM artificial short-circuit test conducted at the photovoltaic power station in Xinjiang.