Distributed control techniques for autonomous AC Microgrid-A brief review

Fuzzy-Based Distributed Cooperative Secondary Control with Stability Analysis for Microgrids

“…Limitations of centralized (single-point of failure) and decentralized (poor dynamic and steady-state response) control strategies have led to distributed control structures [3,6]. Recently, multiagent structures or consensus algorithms [7,8] have received increased attention for their simple control structure utilizing sparse communication systems, improved reliability and acceptable dynamic/steady-state performance [6,[8][9][10]. Nevertheless, the dynamic response of the MG considering distributed secondary control (DSC) could be unexpected in regard to the system oscillation, reaction time, stability margins [10] and steady-state behaviour.…”

“…An improved droop control was suggested in [30], where incorrect reactive power sharing is yet noticed under clearly non-uniform line impedances. In addition, current secondary control approaches are categorized as centralized [31], decentralized [32][33][34] and distributed control [6,8,9,21,35]. This is somewhat motivated by the cooperative control concept for multiagent structures [6,8,9,32,33], letting all distributed energy resources (DERs) connect through their neighbours across local communication systems.…”

“…In addition, current secondary control approaches are categorized as centralized [31], decentralized [32][33][34] and distributed control [6,8,9,21,35]. This is somewhat motivated by the cooperative control concept for multiagent structures [6,8,9,32,33], letting all distributed energy resources (DERs) connect through their neighbours across local communication systems. Maximum distributed reactive power control (DRPC) techniques apply the voltage sensitivity analysis-based scheme [33,36] as per the literature for calculating the exact amount of reactive power, which each DER requires to add for confirming the system voltage maintained within allowable boundaries.…”

“…As a result, a secondary regulation system has been introduced to guarantee a steady frequency profile in the MG [5]. In the existing literature for frequency control and active power sharing, secondary control systems of MGs are generally classified into three groups: centralized [47], decentralized [32,48,49] and distributed [8,9,21,35,36,50,51]. The central controller for frequency restoration also faces the possibility of a single point of failure and could have trustworthiness and scalability concerns [2,8,25,31,49].…”

“…Recently, numerous DSC strategies have been stated in the literature. Most methods are based on consensus practice [4,8,9,[50][51][52][53], where the agents achieve consensus by means of exchanging information over a sparse communication system. The control method described in [51] reports simply frequency restoration through a distributed averaging proportional-integral controller but requires a centralized communication configuration regardless of its decentralized execution.…”