Stability Analysis of Distributed Energy Storage System Considering Multi-Delay Coupling
Yang Ling1,2, Li Jiewen1, Zhu Difan1, Liao Junhao1, Lian Chenxi1
1. School of Automation Guangdong University of Technology Guangzhou 510006 China; 2. State Key Laboratory of High-Efficiency and High-Quality Conversion for Electric Power Hunan University Changsha 410082 China
Abstract：A distributed energy storage system (DESS) is a key component of DC microgrids, effectively mitigating power fluctuations from renewable energy and load demand. However, in DESS based on droop-free control, distributed energy storage units (DESUs) transmit information over sparse communication networks, and the presence of communication and computation delays threatens system stability. Most existing studies employ transfer function models to analyze the stability of DESS with delays. However, such models can only characterize the input-output relationship of the system, failing to describe the complex coupling interactions among internal parameters accurately. Therefore, this paper investigates the influence of delay-parameter coupling on system stability and proposes a stability-optimization method based on multi-delay decoupling. First, given the low-inertia characteristics and communication constraints of DESUs and the sparse inter-DESU communication topology, a detailed small-signal state-space model of DESS is established based on inter-DESU communication. Subsequently, by solving the system's eigenvalue distribution, the dominant modes most sensitive to the system response are identified. The factors influencing these modes are analyzed, revealing that the primary determinants of system stability are communication and calculation delays in the communication link. The variations in the participation of the dominant modes across different delay combinations are quantitatively explored, revealing the coupling among multiple delay parameters and their effects on system stability. Two critical findings are obtained. (1) Compared with a single DESU, the simultaneous increase in communication delay of two or more DESUs increases the system sensitivity to communication delay by at least one order of magnitude, intensifying the coupling of communication delay among multiple DESUs, and significantly reducing the system stability margin. (2) When the communication delay exceeds 5ms, it indirectly increases the contribution of computational delay to the dominant mode via coupling. It causes the dominant modes to move a greater distance for the same magnitude of variation in calculation delay, thereby amplifying the negative impact of calculation delay on stability. The correctness and universality of the obtained conclusion are verified in the case of an increase in the total number of DESUs. The degree of influence of communication and calculation delays on system stability primarily depends on the magnitude of the communication delay. Therefore, a delay-decoupling compensation method is proposed that applies advanced processing to communication channels and actively compensates for delay-induced communication errors. It effectively mitigates the adverse effects of the coupling between communication and computation delays on stability, stabilizes the dominant modes in the left half-plane, and improves overall system stability. Finally, a hardware-in-the-loop experimental platform is established, and experiments verify the correctness and effectiveness of the theoretical analysis and the proposed method. Meanwhile, across scenarios of sudden load increases and fluctuations in energy storage output, the universality of the proposed conclusion is further verified.
杨苓, 李杰文, 朱涤凡, 廖钧濠, 连晨曦. 考虑多延时耦合的分布式储能系统稳定性分析[J]. 电工技术学报, 2026, 41(10): 3482-3499.
Yang Ling, Li Jiewen, Zhu Difan, Liao Junhao, Lian Chenxi. Stability Analysis of Distributed Energy Storage System Considering Multi-Delay Coupling. Transactions of China Electrotechnical Society, 2026, 41(10): 3482-3499.
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