This paper performs an extensive review on control schemes and architectures applied to dc microgrids (MGs). It covers multilayer hierarchical control schemes, coordinated control strategies, plug-and-play operations, stability and active damping aspects, as well as nonlinear control algorithms. Islanding detection, protection, and MG clusters control are also briefly summarized. All the mentioned issues are discussed with the goal of providing control design guidelines for dc MGs. The future research challenges, from the authors’ point of view, are also provided in the final concluding part.

In this article, we examined dc microgrid-based maritime onboard power systems and outlined the need for and potential benefit of employing both smart grid technologies and the MVdc IPS for the future AES to enhance the controllability and efficiency of shipboard power systems. We introduced a series of technical outcomes from research on terrestrial dc microgrids, such as dc power architecture, the application of ESSs, hierarchical control, and different coordination methods. We also presented objective-oriented coordinated management methods and protective functions for future MVdc IPSs, which are to meet the specific need of maritime applications using methodologies from dc microgrids. In the last decade, there were several prototypes of ships on the low-voltage dc level, while, for the MVdc IPS, there are still technological challenges and de-risking studies to be performed. However, it is foreseeable that the advanced technologies from terrestrial dc microgrids are potentially applicable in the MVdc IPS of the future AES. Thus, such a combination will contribute to the implementation of high-performance MVdc IPSs for both commercial and mission-oriented vessels in the near future.

Distributed control methods based on consensus algorithms have become popular in recent years for microgrid (MG) systems. These kind of algorithms can be applied to share information in order to coordinate multiple distributed generators within a MG. However, stability analysis becomes a challenging issue when these kinds of algorithms are used, since the dynamics of the electrical and the communication systems interact with each other. Moreover, the transmission rate and topology of the communication network also affect the system dynamics. Due to discrete nature of the information exchange in the communication network, continuous-time methods can be inaccurate for this kind of dynamic study. Therefore, this paper aims at modeling a complete dc MG using a discrete-time approach in order to perform a sensitivity analysis taking into account the effects of the consensus algorithm. To this end, a generalized modeling method is proposed and the influence of key control parameters, the communication topology, and the communication speed are studied in detail. The theoretical results obtained with the proposed model are verified by comparing them with the results obtained with a detailed switching simulator developed in Simulink/Plecs.

DC distribution is now becoming the major trend of future mobile power systems, such as more-electric aircrafts and ships. As dc distribution has different nature to the conventional ac system, a new design of well-structured control and management methods will be mandatory. In this paper, a shipboard power system with dc distribution and energy storage system (ESS) is picked as the study case. To meet the requirement of control and management of such a large-scale mobile power system, a hierarchical control design is proposed in this paper. In order to fully exploit the benefit of the ESS, as well as to overcome the limitation in controllability, a novel inverse-droop control method is proposed, in which the power sharing is according to the source characteristic, instead of their power rating. A frequency-division method is also proposed as an extension to the inverse-droop method for enabling a hybrid ESS and its autonomous operation. On the basis of the proposed methods, the control methods for management and voltage restoration levels are also proposed to establish a comprehensive control solution. Real-time simulations are carried out to validate the performance of the proposed control design under different operating conditions. When compared to more conventional droop-based approaches, the new proposal shows enhancement in efficiency.