Modular DC-DC Converters on Graphs: Cooperative Control

Modular dc-dc converters are popular in dc-power systems due to their advantageous characteristics such as fault tolerance, ease of thermal management, reducing voltage/current stress of the components, and modularity. In this paper, the concept of cooperative control in multiagent systems is introduced for modular dc-dc converters. Each constituent converter is represented by a node in a directed communication graph that models the information flow among converters. The proposed cooperative control scheme enjoys structural modularity, plug-and-play capability, fault tolerance against random failures in the converters and/or communication links, and satisfactory dynamic performance. This paper provides a general analytical framework to study modular dc-dc converters with an arbitrary communication graph. Hence, the designer has the freedom to choose among the various types of graphs based on the available communication resources and the desired level of reliability and fault tolerance. The dynamic model of the cooperative multiconverter system is developed and analyzed. Hardware measurements are presented to verify the plug-and-play capability, fault tolerance in both cyber and physical domains, and dynamic performance of the proposed cooperative control scheme.