Analysis and implementation of virtual impedance for fixed?frequency control strategy in microgrid

Classic droop control ensures the synchronization of distributed generation (DG) units inside a microgrid without requiring any deployment communication links, however it causes unwanted frequency fluctuations and degrades system dynamics. Angle V ? I have been developed as two major global positioning (GPS)-based methods, both which realize fixed-frequency operation through synchronizing DG with GPS timing technology brings improvement to dynamic response overall system. This paper reveals similarities correlations between these methods that they can be regarded different forms virtual impedance control. A novel adaptive method is proposed accordingly generalize GPS-based strategies into unified frame. An inner controller design approach considering stability constraints power quality requirements based on small-signal model microgrids presented for practical implementation. transient resistance concept adopted enhance during large disturbances grid faults. Case studies are validate performance fault ride-through abilities scheme.