Power sharing through interlinking converters in adaptive droop controlled multiple microgrid system

Multiple microgrids (MMGs) may be interconnected through voltage source converters (VSC) for controlled power sharing among themselves. VSCs in large interconnected micro- grids may use non-communication based droop control to share total power demand in the ratio of their droop coefficients. However, a constant droop ratio restricts the power delivery capability of the VSCs although surplus power may be available in their respective sources. In this paper, along with a unified power management strategy for intra and inter microgrid power sharing in a hybrid AC-DC MMG system, a novel adaptive droop control algorithm is presented that dynamically changes droop coefficients of the VSCs to ensure maximum utilization of available resources in each microgrid under different operating modes. Stability analysis of the proposed control method is performed and comparison of the system performance with fixed and adaptive droop ratio is illustrated by simulating the MMG in MATLAB SIMULINK using real solar irradiance field data. It is validated from simulation results that the adaptive droop control method increases utilization of renewable energy sources within microgrids and reduces energy import from utility grid.