This paper proposes a nonuniform delay-dependent robust secondary voltage control strategy with a finite-time voltage reference observer for an islanded microgrid. A discrete-time consensus algorithm is introduced to track the output voltage. By model transformation, a closed-loop microgrid control system is obtained. And then, the corresponding global stability and robust performance analysis theorems are derived. After implementing a series of trial studies, the impacts of secondary voltage control gains, sampling time on energy-to-peak robust performance are obtained. And the feasible optimal voltage control gains can be derived. Besides, a distributed cooperative secondary frequency control is introduced. Simulations of a four inverter-based microgrid test system are presented to verify the control performance. The simulation results indicate that our proposed method can maintain accurate voltage/frequency restoration and active power sharing. In addition, the voltage control gain parameters, arbitrary nonuniform time delays, and especially sampling time effects on the secondary voltage control performance are also verified.

本文提出了一种基于时滞的非均匀鲁棒二级电压控制策略，该策略具有一个有限时间的电压参考观测器，用于孤岛微电网。引入了离散时间共识算法来跟踪输出电压。通过模型转换，获得了闭环微电网控制系统。然后，推导了相应的全局稳定性和鲁棒性能分析定理。在进行了一系列试验研究之后，获得了次级电压控制增益，采样时间对能量峰峰值鲁棒性能的影响。并且可以得出可行的最佳电压控制增益。此外，介绍了分布式协作式二次频率控制。提出了一种基于四个逆变器的微电网测试系统的仿真，以验证控制性能。仿真结果表明，本文提出的方法可以保持准确的电压/频率恢复和有功功率共享。此外，还验证了电压控制增益参数，任意不均匀的时间延迟，尤其是采样时间对次级电压控制性能的影响。