基于一致性理论的直流微电网分布式控制方法及其关键技术研究

The dc bus voltage control is a key problem for the safe and reliability operation of the microgrid. The conventional decentralized control has the drawback such as low voltage control accuracy and uncertain droop coefficient, and the centralized control suffers from poor reliability and pose stringent requirements on the communication. Moreover, a single point of failure could easily occur and cause the system collapse. Based on the Multi-Agent System consensus theory, the proposal proposes a methodology to satisfy the “plug and play” and “peer to peer” control requirement of microgrid. It can overcome the voltage problem brought by the line impedance, the communication requirement and the topology change and so on. A unified modelling method will be explored to model the dc microgrid system with communication network. Combining with the discrete characteristics of the system model, a consensus algorithm will be designed by considering the delay and the variable communication topology. A hierarchical control scheme is conceived with the information network level and the local controller level to achieve the voltage control accuracy and realize the plug and play function. Finally, a hybrid simulation platform is constructed by introducing the synchronization mechanism to verify the correctness and effectiveness of the model and the methodology. The interact between the communication network and the microgrid voltage stability will be revealed. The project is intended to contribute a novel control methodology to the dc microgrid.

直流母线电压控制是直流微网稳定运行控制研究的关键问题。针对传统分散控制下垂系数选取难、控制精度差以及集中控制对通信要求高、不能自适应控制单元投退的问题，本项目拟基于多智能体一致性理论，提出与直流微电网“即插即用”和“对等”的分布式控制需求相吻合的控制方法，以克服微电网线路阻抗、通信要求、拓扑结构等因素对电压稳定性的影响。通过研究包含通信网络的直流微电网系统统一模型，设计契合该模型特点并且考虑延时和变通信拓扑的离散一致性算法，构建包括信息网络层和本地控制层的直流电压双层控制框架，实现直流电压无偏差控制和控制单元的即插即用；通过研究信息网络和直流微电网联合仿真的同步策略，建立直流微电网信息物理联合仿真平台，验证模型和方法的正确性和有效性，揭示信息网络和直流微电网电压稳定的相互影响机制。本项目可为直流微电网分布式控制提供新思路和新方法。

随着可再生能源渗透率的增加，微电网技术作为未来分布式能源供应系统的主要形式受到了广泛关注。相比于传统交流微电网，直流微电网能够减少逆变器数量，且没有无功潮流控制、频率稳定等问题，是一种更高效的集成分布式电源的方式。储能单元是直流微电网中补偿系统不平衡功率、稳定直流母线电压的主要环节，本项目针对分布式光-储发电单元构成的直流微电网，研究了基于一致性理论的分布式控制策略，实现直流电压无偏差控制以及分布式单元的即插即用。针对复合储能的功率分配问题，本项目提出了一种分散式与分布式结合的复合储能功率分配策略，可实现负载功率在蓄电池和超级电容器之间的合理分配，同时减少对通讯的需求。另外，本项目通过建立直流微电网信息物理联合仿真平台，验证了模型和方法的正确性和有效性，揭示了信息网络和直流微电网电压稳定的相互影响机制。该研究成果为直流微电网的稳定控制及大规模应用提供了理论基础。