An Improved Power Management Strategy for MAS-Based Distributed Control of DC Microgrid under Communication Network Problems

Abstract

In this paper, an improved power management strategy (PMS) for multi-agent system (MAS)-based distributed control of DC microgrid (DCMG) under communication network problems is presented in order to enhance the reliability of DCMG and to ensure the system power balance under various conditions. To implement MAS-based distributed control, a communication network is constructed to exchange information among agents. Based on the information obtained from communication and local measurements, the decision for the local controller and communication is optimally given to guarantee the system power balance under various conditions. The operating modes of the agents can be determined locally without introducing any central controller. Simultaneously, the agents can operate in a deliberative and cooperative manner to ensure global optimization by means of the communication network. Furthermore, to prevent the system power imbalance caused by the delay in grid fault detection and communication in case of the grid fault, a DC-link voltage (DCV) restoration algorithm is proposed in this study. In addition, to avoid the conflict in the DCV control among power agents in case of the grid recovery under communication failure, a grid recovery identification algorithm is also proposed to improve the reliability of DCMG operation. In this scheme, a special current pattern is generated on the DC-link at the instant of the grid recovery by the grid agent, and other power agents identify the grid recovery by detecting this current pattern. Comprehensive simulations and experiments based on DCMG testbed have been carried out to prove the effectiveness of the PMS and the proposed control schemes under various conditions. Sustainability 2020, 12, 122 2 of 27 has been an approach to develop a fast proactive hybrid DC circuit breaker which interrupts the DC fault [5]. As another approach to enhance the reliability, the DC-link voltage (DCV) control method has been presented for MG by the conventional centralized power flow control strategy [6].Depending on the types of bus voltage, MGs can be mainly classified into DC microgrids (DCMGs), AC microgrids (ACMGs), and hybrid AC/DC microgrids [7]. Among them, DCMGs are known to be more attractive due to several advantages as compared with the other configurations. DCMGs provide a convenient interface in connecting various DC loads and operate with better efficiency in transmission and distribution. Moreover, the consideration for the harmonic injection and frequency stability is not necessary. As a result, DCMGs can be considered as an efficient, reliable, and cost-effective option in some applications [8].In view of the communication perspective, the control of DCMGs can be divided into three methods: centralized control, decentralized control, and distributed control [9]. In centralized control, the data from distributed power units are collected in a central controller (CC). Then, the CC processes the acquired data to send the feedback commands back to units via digital communication links (...

Integration of AC/DC Microgrids into Power Grids

“…T. V. Nguyen, et al [10], in their paper entitled "An Improved Power Management Strategy for MAS-Based Distributed Control of DC Microgrid under Communication Network Problems", proposes an improved Power Management Strategy (PMS) using the Multi-Agent System (MAS)-based distributed control of the DC microgrid. In this study, the DC microgrid consists of a grid agent, a battery agent, a wind power generation system agent, and a load agent.…”

Simulation of Power Router-Based DC Distribution Systems with Distributed Generation and Energy Storage Units

“…The paper [23] proposes an effective strategy for power flow control in the event of network failures based on the method of centralized control and the algorithm for restoring reliable voltage in a DC network consisting of a system of wind turbines, power storage devices, and DC loads. Nguyen et al [24] propose a distributed DC microgrid control based on a multi-agent system. In this case, the DC microgrid consists of a network agent, a battery agent, a wind power generation system agent, and a load agent.…”

A Centralized Power Flow Control Scheme of EV-Connected DC Microgrid to Satisfy Multi-Objective Problems under Several Constraints

“…To maintain the power quality under these conditions, adequate coordination between MG systems and main grids is required. MG control schemes are divided into three categories in terms of coordinating power agents: the centralized control scheme, decentralized control scheme, and distributed control scheme [18]. The decentralized control method is known to have the highest flexibility and scalability among the three schemes.…”

“…To prove the feasibility of the proposed power flow control scheme, the Powersim (PSIM) software (9.1, Powersim, Rockville, MD, USA) is used in this work to carry out the simulation [32]. This software has been used to simulate a microgrid system in several works [10,18,20,33]. The simulation setups validate that the proposed scheme regulates the DC-link voltage stably and reliably regardless of a sudden EV connection and disconnection with the DCMG, even when the prime objective of the DCMG operation is immediately changed, or the electricity price conditions are varied.…”