基于观测器的有向通信下多母线直流微电网分布式自触发二次调节

Observer-based Distributed Self-triggered Secondary Control of Multi-bus DC Microgrid Over Directed Communication

基于动态一致性的均值观测是多母线微电网分布式二次调节的常用方法,然而,当前该方法通信和计算频率高,而现有针对静态一致性的自触发方法难以直接应用于动态一致性上,且并未考虑有向通信网络平衡性可能引起的观测误差和二次调节误差等问题。因此,该文提出有向通信下基于观测器的分布式自触发二次调节策略。首先,为直流微电网设计基于动态一致性的分布式平均状态观测器,定量证明在权重平衡有向通信网络下的收敛特性。基于观测器设计分散式二次调节器,并证明该二次调节结构可等效为虚拟全连接通信拓扑,具有良好的动态性能。然后,设计基于分布式自触发的通信和更新机制,实现微源-微源间、微源-远端母线电压采集器间的间歇式通信以及触发式电流和平均母线电压二次调节,并证明李雅普诺夫稳定性。最后,设计触发时间修正方法,提高自触发响应速度。MATLAB/Simulink仿真表明,相比无触发二次调节,准稳态时,可降低二次调节系统通信频率95%、计算频率75%;相比现有自触发方法,可降低平均触发频率54.6%,进而更加有效地降低系统通信和网络负载,提高二次调节系统的实用性和可靠性。

Dynamic consensus-based average state observation is a common method for distributed secondary control (SC) of multi-bus microgrids. However, this method requires high communication and computation frequency, and currently available methods for static average consensus are not applicable for dynamic consensus. Meanwhile, it is not considered that the unbalanceness of directed networks can result observation and SC errors. Therefore, an observationbased distributed self-triggered SC strategy is proposed in this paper. First, a dynamic consensus-based distributed average state observer is designed for DC microgrids, and the convergence under weight-balanced directed networks is proved. Decentralized observation-based SC is designed and the SC structure is proved to be equivalent to a virtually fully connected network with good dynamic performance. Then, a distributed self-triggered mechanism is proposed to achieve intermittent communication between generator - generator and generator - networked sensors as well as intermittent SC computation, thus proving Lyapunov stability. Finally, a trigger time corrector is designed to improve the self-trigger response speed. MATLAB/Simulink simulations show that the proposed method can reduce communication and update frequencies of SC by 95% and 75% in quasi-steady states compared with periodical SC. Furthermore, it reduces the trigger frequency by 54.6% compared with currently available method. The communication and computation burden can be effectively lowered, and system practicability as well as reliability can be significantly improved.