Abstract
As an advanced control method that could bring extra inertia and damping characteristics to inverter-based distributed generators, the virtual synchronous generator (VSG) has recently drawn considerable attention. VSGs are expected to enhance the frequency regulation capability of the local power grid, especially the AC microgrid in island mode. However, the cost of that performance promotion is potential instability. In this paper, the unstable phenomena of the islanded microgrid dominated by SGs and distributed generators (DSs) are addressed after mathematical modeling and detailed eigenvalue analyses respectively. The influence of VSG key parameters, e.g., virtual inertia, damping factor, and droop coefficient on system stability is investigated, and the corresponding mathematical calculation method of unstable region is obtained. The theoretical analysis is well supported by time domain simulation results. The predicted frequency oscillation suggests the consideration of stability constrain during the VSG parameters design procedure.
Highlights
In order to solve environmental problems and energy crisis, distributed generators (DGs) with renewable energy sources (RES), e.g., photovoltaic and wind turbines have been quickly developed.The installed capacities of wind power, solar power, and hydropower in China reached 338 GW, 154 GW, and 102 GW halfway through 2017 [1]
A microgrid typically consists of DGs, energy storage units, and distributed loads that may operate in grid-connected mode or in island mode [3]
This paper focuses on the two kinds of islanded microgrids, synchronous generators (SGs)-dominated islanded microgrid and DG-dominated islanded microgrid
Summary
In order to solve environmental problems and energy crisis, distributed generators (DGs) with renewable energy sources (RES), e.g., photovoltaic and wind turbines have been quickly developed. The grid-connected power electronic inverters are usually needed to regulate the power forms that the DGs primary generate, and the inverters employing popular current source control methods provide less inertia and damping than conventional SGs to the power grid. They are unable to contribute to the improvement of system stability. The unstable region of the islanded AC microgrid with VSG is investigated, to guide the choices of virtual inertia and damping constant.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
