Input-series-output-parallel (ISOP) isolated bidirectional direct current (dc)/dc converter (IBdc) becomes a preferred scheme connecting high-voltage and low-voltage bus in dc distribution network. Input-voltage-sharing (IVS) among modules is essential to realize the stable operation of ISOP system. Nowadays, with large-scale access of distributed energy sources and loads in dc grids, the fluctuations in bus voltage and connected load become frequent and great, deteriorating the IVS performance and stable operation of ISOP structure IBdc. To solve this issue, a triple-close-loop IVS strategy is proposed in this article. Compared with the conventional IVS strategy with constant input impedance, the proposed IVS strategy reshapes input impedance to be a full-order model containing high-order components and sensitive to fluctuation of output voltage, and IVS control based on reshaped impedance improves dynamics feature, maintains ideal output power, and avoids false protection and potential instability for ISOP structure IBdc under frequent and large fluctuation. Experimental results verify the correctness and effectiveness of the analysis and proposed strategy, providing a feasible, efficient, and practical control scheme for ISOP system in dc distribution network.

中文翻译：

---

直流配电网输入串输出并联隔离双向DC/DC变换器输入均压控制策略


输入串输出并联（ISOP）隔离式双向直流（dc）/直流变换器（IBdc）成为直流配电网高低压母线连接的首选方案。模块之间的输入电压共享（IVS）对于实现ISOP系统的稳定运行至关重要。目前，随着分布式能源和负载大规模接入直流电网，母线电压和连接负载的波动变得频繁且剧烈，恶化了ISOP结构IBdc的IVS性能和稳定运行。为了解决这个问题，本文提出了一种三重闭环IVS策略。与传统的恒定输入阻抗的IVS策略相比，所提出的IVS策略将输入阻抗重塑为包含高阶分量且对输出电压波动敏感的全阶模型，并且基于重塑阻抗的IVS控制改善了动态特性，保持了理想的输出功率，避免了ISOP结构IBdc在频繁、大的波动下的误保护和潜在的不稳定。实验结果验证了分析和提出策略的正确性和有效性，为直流配电网ISOP系统提供了可行、高效、实用的控制方案。