Control and fault analysis of multiport converters for low voltage DC distribution systems

The recent evolution of distribution systems has shed light on innovative solutions aimed at enhancing the performance of such systems. In this paper, the authors focus their attention on two modular, non-isolated multiport DC/DC converters and their application to low voltage DC distribution systems. The first topology is based on a capacitive internal link, while the second one is based on a less usual inductive link. Unconventional control strategies based on a lower-level pseudo-sliding mode control algorithm and a higher-level control based on inverse dynamics are proposed for both topologies by means of a general, fully modular control design. A six-port application is discussed in detail and its operation is analyzed in steady state, under abrupt load/generation changes and in case of pole-to-pole faults. Finally, a systematic comparison between the two topologies is performed.