Grid supporting nonlinear control for AC-coupled DC Microgrids

Direct Current (DC) Microgrids have risen as a good option for better integrating distributed renewable energies and various highly dynamic DC loads, such as electrical vehicle supply equipment or industrial grids. However, for the large-scale deployment of such DC Microgrids, developing enhanced control strategies for these inverter-based, highly dynamic grids is crucial. The present paper introduces an innovative nonlinear control tailored for DC Microgrids supporting Alternative Current (AC) grids. Building upon existing methods, we extend the nonlinear control paradigm by incorporating multiple batteries and an AC link. This integration not only bolsters support for the AC grid, but also enhances the stability of DC voltage. We validate the effectiveness of the proposed algorithm through experimental evaluations conducted on a Power Hardware-in-the-Loop (PHIL) DC Microgrid configuration and compare it to a cascaded PI controller based on a linearized model.