Robust Centralized Control for DC Islanded Microgrid Considering Communication Network Delay

Abstract

In recent years, the application of renewable energy resources (RES) with DC output has increased, and RES integration as DC islanded microgrids (DC ImGs) has attracted the attention of many researchers. However, DC ImGs face many challenges, and voltage stability is extremely critical for efficient power distribution. This challenge becomes more prominent when exogenous disturbances, as well as time-delay, exist in the system mainly because of the communication network. In this study, we develop a mathematical model of the time-delay DC ImG. To compensate for the effect of the time-delay, three control strategies are introduced-stabilizing, robust, and robust-predictor. The controller's stability is guaranteed based on the Lyapunov-Krasovskii theorem, whereas for the exogenous disturbance rejection, the L 2-norm of the system is reduced. Furthermore, to obtain the proposed controllers' gains, linear-matrixinequality constraints are formulated. The performances of the controllers are investigated through numerous simulations, and a detailed analysis is presented.

A Power Flow Control Strategy for Hybrid Control Architecture of DC Microgrid under Unreliable Grid Connection Considering Electricity Price Constraint

“…As for the decentralized control approach, the number of the power agents can be increased or decreased easily in the MG system. However, this scheme is lack of coordination to achieve an optimum solution [17] because the communication link does not exist.…”

A brief review on microgrids: Operation, applications, modeling, and control

“…Describe the microgrid control methodCentralizedIn this case, the central processing unit collects all the measurement and decides next action for coordinated operation inside microgrid Mehdi et al148,149 Decentralized It uses local measurements. Also, based on predefined algorithms embedded in each node, decisions are made at the component level Li et al150,151 …”

A New Consensus-based Distributed Adaptive Control for Islanded Microgrids

“…The secondary control layer (SCL) is utilized to overcome this drawback and compensate for f & V deviations result from the droop control method. The SCL can be implemented in three manners: centralized [10][11][12], decentralized [13,14], and distributed [15][16][17][18][19][20][21]. The centralized control method employs a central control module and a communication grid between each DG and the central controller.…”

“…Therefore, it demands extensive communication system to collect and process the massive information of all DGs. As a result, this control method suffers from the drawbacks of the presence of a single point of failure and low reliability [10]. The decentralized control strategy is not usually employed in the secondary control due to the lack of sufficient information to coordinate and harmonize all available MGs resources [13,14].…”

“…The effects of delays and noises in communication channels among DGs have been discussed by Shahab et al [29] thorough stochastic and/or distributed time-delay control methods. Moreover, detail discussion about communication delays' effect on the control of an islanded MG has been investigated by a small-signal model in literature [10,18]. A distributed voltage averaging method was proposed by Amoateng et al [22] to provide a simple compromise between the incompatible objectives of bus voltages regulating and good reactive power sharing.…”