Abstract DC bus voltage restoration, proportional load/power-sharing, and batteries’ SOC balancing are some of the most critical challenges of DC microgrids. The utilization of communication links and the central controller eliminate these problems. Nevertheless, microgrids controlled in this way, have low modularity, flexibility, reliability, and high costs and complexity. This paper proposes a novel communication-less control method, which solves the mentioned concerns and problems. The energy storage units are controlled by local parameters in order to guarantee the system stability. In this method, a unit (sender unit) estimates the DC bus voltage deviation and injects an AC signal to the DC bus. The droop curve of the units is shifted based on the AC signal and their SOC. The shifted values are specified such that the higher SOC units inject (absorb) more (less) power, and the DC bus voltage is restored. The stability analysis and step response of the system show that the proposed method benefits from an acceptable stability and satisfactory speed. Simulation results confirm that the proposed method can regulate the DC bus voltage and reduce the units’ SOC imparity without any communication links and central controller.

中文翻译：

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一种基于交流信号注入改善直流微电网性能的新型无通信控制方法

摘要 直流母线电压恢复、比例负载/功率分配和电池的 SOC 平衡是直流微电网的一些最关键的挑战。通信链路和中央控制器的使用消除了这些问题。然而，以这种方式控制的微电网具有低模块化、灵活性、可靠性以及高成本和复杂性。本文提出了一种新的无通信控制方法，解决了上述关注点和问题。储能单元由本地参数控制，以保证系统的稳定性。在这种方法中，一个单元（发送单元）估计直流母线电压偏差并将交流信号注入直流母线。单元的下垂曲线根据交流信号及其 SOC 发生变化。指定偏移值，以便更高的 SOC 单元注入（吸收）更多（更少）的功率，并恢复直流母线电压。系统的稳定性分析和阶跃响应表明，所提出的方法受益于可接受的稳定性和令人满意的速度。仿真结果证实，该方法可以在没有任何通信链路和中央控制器的情况下调节直流母线电压并降低机组的SOC不平衡性。