Compared to AC microgrids, DC microgrids have the advantage of higher reliability and efficiency and are convenient to connect with various distribution energy resources (DERs). Concentrated in different time-scale control objectives, a multi-level control structure can guarantee that none of the control objectives affect each other. Considering this, an extensive review on the hierarchical structure of the DC microgrid is applied, and two typical control structures are presented in detail: two-level control architecture and three-level control architecture. Furthermore, the primary, secondary, and tertiary control levels are systematically analyzed and classified according to different control objectives. In order to improve the control capability of the primary control level, an energy efficiency improved DC bus voltage control strategy is proposed to increase the energy efficiency and system reliability. Finally, a distributed DC microgrid model is established and simulated in the RT-LAB to verify the effectiveness of the proposed control strategy.

与交流微电网相比，直流微电网具有更高的可靠性和效率，并且方便与各种配电能源（DER）的连接。集中在不同的时间尺度控制目标上的多级控制结构可以保证没有一个控制目标相互影响。考虑到这一点，对直流微电网的分层结构进行了广泛的审查，并详细介绍了两种典型的控制结构：两级控制体系结构和三级控制体系结构。此外，系统会根据不同的控制目标对主要，次要和三次控制级别进行系统分析和分类。为了提高初级控制水平的控制能力，提出了一种提高能效的直流母线电压控制策略，以提高能效和系统可靠性。最后，建立了分布式直流微电网模型，并在RT-LAB中进行了仿真，以验证所提出的控制策略的有效性。