Modeling And Control Of Virtual Synchronous Generator Based Distributed Generators In Microgrid

In recent years,distribution networks have been faced with an increasing penetration of small-scale distributed generators(DGs)(e.g.wind turbines,solar energy)in the form of microgrids.This effectively alters its passive nature resulting in bi-directional power flows and several other major adverse impacts,e.g.voltage rise,increased fault levels,altered transient stability and degradation of protection.Currently,outstanding technical challenges remain for efficiently managing a massive number of inverter-based renewable energy sources,e.g.photovoltaic,fuel cell and micro wind turbine,due to their intermittent and stochastic nature.To this end,this work investigated a novel virtual synchronous generator(VSG)based multi-loop control solution aiming to efficiently manage the inverter-based renewable DGs in a plug-and-play fashion.A novel VSG-based method is adopted to realize the distributed control among DGs,while producing similar external characteristics as synchronous generator to add inertia to the system.Compared with existing methods,the solution in this work is based on a multi-loop feedback control scheme to improve the dynamical and static performance.In addition,an improved vector orientation method based on virtual flux oriented control(VFOC)is proposed to improve the voltage orientation accuracy and realize the zero-error tracking of the grid voltage and ensures smooth interconnection.Finally,a fuzzy control based parameter adaptive control is proposed to restrain system oscillation by self-adaptive adjustment of virtual inertia to obtain improved performance under dynamics.The proposed control solutions is assessed through a set of simulation experiments in a microgrid for both island and grid-connected scenarios,and the numerical results confirm the performance improvements and technical benefits.