Plug-and-play robust voltage control of DC microgrids

The purpose of this paper is to explore the applicability of linear time-invariant dynamical systems with polytopic uncertainty for modeling and control of islanded dc microgrids under plug-and-play (PnP) functionality of distributed generations (DGs). We develop a robust decentralized voltage control framework to ensure robust stability and reliable operation for islanded dc microgrids. The problem of voltage control of islanded dc microgrids with PnP operation of DGs is formulated as a convex optimization problem with structural constraints on some decision variables. The proposed control scheme offers several advantages including decentralized voltage control with no communication link, transient stability/performance, PnP capability, scalability of design, applicability to microgrids with general topology, and robustness to microgrid uncertainties. The effectiveness of the proposed control approach is evaluated through simulation studies carried out in MATLAB/SimPowerSystems Toolbox

Line-independent plug-and-play voltage stabilization and L2 gain performance of DC microgrids

The plug-and-play nature of distributed generation (DG) units in converter-interfaced microgrids imposes significant challenges from the control point of view, mainly caused by the time-varying microgrid structure. In this paper, we propose a systematic plug-and-play decentralized voltage control solution for DC microgrids. The proposed control approach guarantees the stable operation and satisfactory performance of microgrids under the arbitrary interconnection of DG units. Based on the Lyapunov method, concise stability and L2 gain voltage tracking performance certificates for DC microgrids are derived. The main feature of the proposed control approach is the decentralized design of local voltage controllers in DC microgrids. The proposed voltage control framework is applied to a case study of a multiple-DG DC microgrid in MATLAB/Simscape Electrical environment

A distributed control strategy for parallel DC-DC converters

This letter addresses the problem of voltage regulation and balanced current sharing in a parallel connection of heterogeneous DC-DC converters sharing a common ZIP (constant impedance, constant current, and constant power) load. To this end, a distributed dynamic control approach is developed. The proposed control approach does not rely on the load profile and the number of active converters. This letter describes theoretical aspects in rigorous Lyapunov-based stability analysis, load-independent characteristic, scalability, and plug-and-play feature of the control design, and verifies the performance of the proposed control mechanism via simulation case studies in MATLAB/Simscape Electrical environment

Plug-and-play voltage stabilization in inverter-interfaced microgrids via a robust control strategy

This paper proposes a decentralized control strategy for the voltage regulation of islanded inverter-interfaced microgrids. We show that an inverter-interfaced microgrid under plug-and-play (PnP) functionality of distributed generations (DGs) can be cast as a linear time-invariant system subject to polytopic-type uncertainty. Then, by virtue of this novel description and use of the results from theory of robust control, the microgrid control system guarantees stability and a desired performance even in the case of PnP operation of DGs. The robust controller is a solution of a convex optimization problem. The main properties of the proposed controller are that: 1) it is fully decentralized and local controllers of DGs that use only local measurements; 2) the controller guarantees the stability of the overall system; 3) the controller allows PnP functionality of DGs in microgrids; and 4) the controller is robust against microgrid topology change. Various case studies, based on time-domain simulations in MATLAB/SimPowerSystems Toolbox, are carried out to evaluate the performance of the proposed control strategy in terms of voltage tracking, microgrid topology change, PnP capability features, and load changes

A fully resilient cyber-secure synchronization strategy for AC microgrids

This letter focuses on resilient synchronization in networked AC microgrids under cyber-attacks, where attackers aim to desynchronize converters by injecting bounded false data to communication and control channels. To this end, a resilient cooperative control framework for the secondary frequency regulation in AC microgrids is developed. The proposed resilient distributed control strategy achieves synchronization regardless of the existence of cyber-attacks. Moreover, it offers the maximum level of resilience, i.e. it guarantees resilient synchronization even if all distributed generation units in microgrids are subject to cyber-attacks. Theoretical analysis and verification case studies are carried out in order to demonstrate the advantages and performance of the proposed resilient cooperative control