基于单输入单输出传递函数的构网型储能系统交互建模与稳定性分析

With the rapid expansion of photovoltaic (PV), grid-forming energy storage systems (GFM-ESS) have been widely employed for inertia response and voltage support to enhance the dynamic characteristics. Converters with different synchronization methods represent significant differences in dynamic behavior. The interactions between grid-forming (GFM) and grid-following (GFL) devices with multi-time scale control may lead to small-signal instability in hybrid systems. This paper investigates a grid-connected system comprising a grid-forming energy storage system and a grid-following PV system (GFL-PV). Based on single-input-single-output (SISO) transfer functions, a dynamic interaction model for the PV-ESS system is established. Combining the open-loop transfer functions of full-loop and sub-loop, the proposed model reveals how GFM-ESS modifies the dynamic characteristics of GFL-PV under weak grid conditions. Subsequently, the impact of different control loops and parameters on the small-signal stability of the system is analyzed. The stability margins of both devices are also compared through the SISO model. Electromagnetic transient simulation results in MATLAB/Simulink and experiments validate the effectiveness of the proposed models and analyses.