Topology and control design of converters for short-circuit fault protection in DC microgrids

Abstract

In this paper, power electronics building blocks are examined and exploited for protection of the short-circuit faults in the DC Microgrid systems. An AC-DC converter topology is suggested to commit the protection, and its short-circuit characteristics are presented. Specialized control schemes for short-circuit protection are proposed for the converter. On the basis of the two-loop current-mode control, variable-frequency control and output power feed-forward control are applied to improve the current-limiting operation at fault events. The short-circuit current is limited by the converter of which the loop characteristic under the fault case is studied for stable operation. The proposed short-circuit protective converter and the control schemes are verified through simulations.