Analysis and design of LCL filter based synchronverter

Electrical energy generation is evolving from centralized towards distributed energy resources (DER) like wind and solar power plants. In such power systems, new challenges arise for the design of voltage source converter (VSC) control strategies. In the last few years synchronverters have gained interest from the research community due to their capability of emulating synchronous machines (SMs) and therefore, in combination with energy storage systems, providing additional virtual inertia to the system. Furthermore, due to their intrinsic power synchronization mechanism, they are able to self-synchronize themselves to the grid without the need of a dedicated synchronization unit. In order to investigate the features of this type of controller, in this paper the small-signal analysis of a system consisting of a Synchronverter connected to the grid through an output LCL filter is presented. The results of the developed model will be compared first to time domain EMT simulations in MATLAB/Simulink/PLECS and subsequently to laboratory experiments, in order to prove their validity. The developed tool will be used for design purposes and to investigate the effects of parameters variation on the dynamic response of the system. Based on these considerations, a design procedure for a synchronverter will be presented.