交直流微电网集群柔性控制及稳定性分析

Flexible Control and Stability Analysis of AC/DC Microgrids Clusters

该文重点关注柔性互联交直流微电网集群分层多尺度协调控制框架中的就地控制(即稳定控制)问题。现有的确定性控制策略一方面难以有效应对紧急情况下交直流微电网集群运行控制模式的平滑切换,另一方面为实现功率协调控制须依赖通信。为解决上述问题,提出一种全新的控制策略以区别于现有的确定性控制方法,称之为交直流微电网集群柔性控制方法。应用该柔性控制方法,交直流微电网集群中各装置就地控制不再依赖于某个特定的运行模式,易于实现运行模式平滑切换。更重要的是,仅依靠就地量测的电气量信息,即可实现多微电网集群功率协调控制。从稳态和小信号建模及稳定性分析两方面,论述了所提柔性控制方法的有效性。最后,在PSCAD/EMTDC中搭建了包含2个直流微电网、1个交流微电网,以及隔离DC-DC和DC-AC互联装置的多微电网柔性互联集群仿真算例,对所提方法进行了有效验证。

This paper focused on the problem of local control stability control in a hierarchical multi-scale coordination control framework for flexible interlinking AC/DC MGs clusters. On one hand, the existing deterministic control strategy is difficult to effectively deal with smooth transition issue of the AC/DC MGs clusters operation control mode in emergencies, and on the other hand, the power coordination control must rely on communication. In order to solve the above problems, a new control strategy called AC/DC MGs clusters flexible control method was proposed to distinguish it from the existing deterministic control method. Applying the flexible control method, the local control of each device in the AC/DC MGs clusters no longer depends on a specific operation mode, and it is easy to realize smooth transition of the operation mode. More importantly, it only relies on the local measurement of electrical quantity information to achieve MGs clusters power coordination control. This paper discussed the effectiveness of the proposed flexible control method from two aspects: one is steady state and the other one is small signal modeling and stability analysis. Finally, a simulation example of multi-microgrid flexible interlinking clusters consisting of two DC microgrids, an AC microgrid, and isolated DC-DC and DC-AC interlinking devices were built in PSCAD/EMTDC, which verified the proposed method effectively.