The Operating Characteristics And Control Scheme Of Microgrid Dominated By Virtual Synchronous Generator Microsource

With the tendency of renewable energy power generation integrated to the grid in large scale,the large number of grid-connected power electronic converters will negatively influence the stability of grid because of its fast response speed and the fact that they almost have no moment of inertia.In order to improve the situation,A new inverter control strategy named Virtual Synchronous Generator(VSG)is proposed which makes inverter exhibit the same external characteristics as the traditional synchronous generator as well as inertia and damping response characteristics.This kind of gird-friendly property makes it significantly valuable for research and future engineering application.In this paper,the current research status of microgrid control schemes,the emergence and development of VSG are reviewed first.Then the overall structure of the PV-BESS microgrid is constructed according to the actual needs of engineering.The mathematical models of its PV and BESS microsource are derived and analyzed in detail,their respective control strategies are elaborated as well.In addition,the framework of microgrid's hierarchical control is also presented.Next,the crucial parameters of the models are derived,followed by the steady-state performance and transient response analysis in grid-connection and islanded mode of the microgrid which is based on the mathematical model and the derived parameters.The theoretical results are obtained which show that the PV-BESS microgrid can spontaneously participate in the frequency and voltage regulation of the system.Moreover,its steady-state performance is good and it can maintain safe continuous operation when faced with a certain degree of transient shocks,while achieving seamless switch between gridconnection and islanded mode.At last,the response of the microgrid in steady-state and transient situations is simulated and verified on the realtime simulation platform which is based on the Real Time Digital Simulator(RTDS).The consequences confirm the previous analysis and present some new findings at the same time,which lead to a comprehensive understanding of the operating characteristics and control schemes of the PV-BESS microgrid dominated by VSG microsource.Additionally,it provides new perspectives for future research in the meantime.