As microgrids develop rapidly, more inverters are adopted to achieve DC/AC or AC/DC/AC conversion of distributed generators (DGs). The virtual synchronous generator (VSG) control has started to replace the traditional droop control for inverters. In order to restore the frequency to its nominal value, most existing secondary frequency control (SFC) methods are based on frequency measurements. However, while reducing the rate of change of frequency (ROCOF), virtual inertia also slows down the convergence of frequency-based SFC. Therefore, this paper proposes a new distributed hierarchical control for fast frequency restoration. Based on the real-time VSG control at the bottom level, a novel frequency restoration control is designed. The power reference values generated by the proposed control can accelerate the frequency restoration with accurate power sharing. Meanwhile, by designing event-triggering conditions, parallel inverter controllers only need to communicate with neighbors at the event-triggered moments. Simulations have been performed in MATLAB/Simulink environment. Furthermore, the proposed control has also been tested on the experiment platform, which contains practical physical circuits and real-time controllers. Both simulation and experiment results verify the effectiveness of the proposed control strategy.

中文翻译：

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VSG控制孤岛微电网中快速频率恢复的分布式分级控制


随着微电网的快速发展，越来越多的逆变器被用来实现分布式发电机（DG）的DC/AC或AC/DC/AC转换。虚拟同步发电机（VSG）控制已开始取代传统的逆变器下垂控制。为了将频率恢复到其标称值，大多数现有的二次频率控制（SFC）方法都是基于频率测量。然而，虚拟惯性在降低频率变化率（ROCOF）的同时，也减慢了基于频率的SFC的收敛速度。因此，本文提出了一种新的分布式分层控制用于快速频率恢复。基于底层实时VSG控制，设计了一种新颖的频率恢复控制。由所提出的控制生成的功率参考值可以通过精确的功率共享来加速频率恢复。同时，通过设计事件触发条件，并联逆变器控制器只需在事件触发时刻与邻居进行通信。仿真已在 MATLAB/Simulink 环境中进行。此外，所提出的控制也在包含实际物理电路和实时控制器的实验平台上进行了测试。仿真和实验结果验证了所提出控制策略的有效性。