A Robust Active Stabilization Technique for DC Microgrids with Tightly Controlled Loads

Recent advancements in stability analysis of DC microgrids have enabled optimized system designs with reduced sizes of passive elements and improved performance of regulators. Reduced size of passive elements provides savings in cost, weight, and space which is of special interest in electrified transportation systems. However, smaller capacitance for DC-link may make the system more susceptible to instability. Different active stabilization techniques have been proposed in the literature to compensate for this issue. This paper proposes a large-signal stabilization technique to expand the global stability margins, while keeping the benefits of the small capacitor sizes. The presented stabilizing control method takes into account measurements and parameters uncertainties to provide a robust solution to the mentioned stability problem. To validate the method, simulation and experimental results are presented for a power electronic-based DC microgrid that consists of a voltage source inverter driving a PMSM, a boost converter incorporating a supercapacitor, and a buck converter supplying a resistive load.