直流微电网分布式控制的时滞稳定化设计

The design of delay stability in DC microgrids with distributed control

直流微电网中,大部分控制器在设计时未考虑通信延时对系统性能的影响,这可能会导致控制器在实际应用中失效甚至影响系统的稳定性.本文基于一种分布式控制策略,建立了直流微电网系统的时滞模型,重点研究了通信延时对系统稳定性的影响.结合Razumikhin稳定性理论,提出了一种针对时变时滞系统的全时滞稳定性判据.为了更加适用于实际系统,在另一种全时滞稳定性判据的基础上,对系统时滞相关稳定性进行分析,得到保证系统稳定的延时上界,进而给出了一种确定控制参数范围的方法.与传统的将通信延时处理为一阶惯性环节的分析方法相比,基于时滞系统的分析方法更切合实际,为系统的稳定运行提供了一个更宽的时滞范围,提高了系统的可靠性.仿真和实验结果表明本文提出的控制参数设计方法能保证系统在最大延时下的稳定运行.

The impact of communication delay on direct-current(DC)microgrids performance has been neglected normally in most controller designs,which may cause system instability.The effect of communication delay on system stability is studied based on a distributed control strategy.Combined with Razumikhin stability theory,a novel delayindependent stability criterion for the system with time-varying delays is proposed based on another delay-independent stability criterion,the delay-dependent stability of the system is analyzed for practical application,and the delay upper bound which can guarantee the system stability is given.Specifically,an approach which defines the feasible regions of control parameters is derived to guarantee the system stability under the condition of delay.Compared with the first-order inertia loops,this method provides a wider delay boundary,which makes the system safer,more reliable and stable.Finally,simulation and experimental results verify that the feasible regions of control parameters can guarantee the system stability under maximum delay.