新能源直流微网的控制架构与层次划分

以新能源直流微网为研究对象,融合集中控制和分散控制特点,提出一种直流微网层次控制架构。根据直流微网的物理特性,将控制框架划分为变流器控制层、母线控制层和调度管理层。在变流器控制层,将各类变流器统一为终端控制型和母线控制型;在母线控制层,根据母线电压划分3种运行模式,以实现系统中各单元的自适应模式切换;在调度管理层,中央控制单元通过自上而下的决策仲裁机制,实现系统的整体优化。位于底层的变流器控制层通过分散自治控制保证系统的可靠性;处于顶部的调度管理层通过集中控制提升系统的灵活性;处于中间的母线电压控制层作为重要衔接,实现系统的能量流动和信息交互。最后,通过理论分析和实验测试,验证了所述控制策略的有效性。

Control Architecture and Hierarchy Division for Renewable Energy DC Microgrids

The hierarchical control architecture for a renewable energy microgrid is developed, which combines the advantages of centralized and distributed control to enhance reliability and flexibility. According to the physical characteristics of a DC microgrid, the control architecture is divided into three levels, namely, the converter control level, bus regulation level and dispatch managing level. At the converter control level, various kinds of converters in a microgrid system can be categorized into terminal regulating converters and bus regulating converters according to external control targets. At the bus control level, the DC bus voltage of the microgrid system is divided into three ranges corresponding to three system operation modes. Each unit switches adaptively between the terminal regulating converters and bus regulating converters according to the variation of DC bus voltage. At the dispatch managing level, the microgrid control center adjusts the output characteristic curve of each unit to achieve further advanced functions. The converter control level at the bottom ensures high reliability operation by distributed autonomous control; the dispatch managing level at the top promotes global optimization by centralized decision making, whilethe intermediary bus control level serves as a bridge in between. A test platform is implemented to verify the effectiveness of the control hierarchy. This work is supported by National Basic Research Program of China (973 Program) (No. 2014CB247400).