Unified model for droop control inverters operated in microgrid

Inverter is widely used in microgrids. Inverter's control strategy plays very important role for its performance and system stability. Several control strategies are proposed, such as droop control, robust droop control and virtual synchronous generator (VSG) control. In microgrid, inverters manufactured by different factories with different control strategies work together. This situation is not good when modelling, analysing and managing microgrid. It naturally rises a question: could these controllers be unified as a unified one? Although some comparisons have been made and proved they have some common characteristics, but there lies no explicit unified controller. In this paper, after investigation of three most common inverter control strategies in microgrid, the unified inverter model is proposed. Simulation results via MATLAB/Simulink software prove that the proposed unified model can be used to represent other three inverters' controllers. A microgrid scheme is used to explain application of the unified model. This research will benefit the design of inverter control strategy and simplify microgrid modelling.