A Novel Distributed Secondary Coordination Control Approach for Islanded Microgrids

Abstract

This paper develops a new distributed secondary cooperative control scheme to coordinate distributed generators (DGs) in islanded microgrids (MGs). A finite time frequency regulation strategy containing a consensus-based distributed active power regulator is presented, which can not only guarantee the active power sharing but also enable all DGs' frequencies to converge to the reference value within a finite time. This enables the frequency and voltage control designs to be separated. Then an observer-based distributed voltage regulator involving certain reactive power sharing constraints is proposed, which allows different set points for different DGs and, thus, accounts for the line impedance effects. The steady-state performance analysis shows that the voltage regulator can accurately address the issue of global voltage regulation and accurate reactive power sharing. Moreover, all the distributed controllers are equipped with bounded control inputs to suppress the transient overshoot, and they are implemented through sparse communication networks. The effectiveness of the control in case of load variation, plugand-play capability, communication topology change, link failure, time delays and data drop-out are verified by the simulation of an islanded MG in MATLAB/SimPowerSystems.

MAS-Based Distributed Coordinated Control and Optimization in Microgrid and Microgrid Clusters: A Comprehensive Overview

“…Under this circumstance, the cost of the MG will be increased and the stability of system can be undermined [142]. Therefore, decentralized control strategy have been proposed to solve the problems in the centralized control [143]. The decentralized control does not rely on a MGCC and droop mechanism, so the error of a DG unit will not produce the failure of the entire system.…”

Cyber-physical cooperative control strategy for islanded micro-grid considering communication interruption

“…But when using this method, there is also a biggest problem: The obtained output frequency and voltages of the controlled DERs are not the reference values. [15][16][17][18] Therefore, the secondary control is usually required to adjust the output frequency and voltages of DERs again. 19 And there were a lot of researches on secondary control, such as a two-level decentralized optimization power-dispatch control was proposed in Dou et al 20 There were two layers of the control strategy (the lower layer of the strategy is to control the operation of DER, and the upper layer is for optimize the control effect).…”

“…It is similar to the secondary voltage control; the role of the secondary control on frequency is to make ω i → ω ref . Based on the differential equation of Equation 18 and set an auxiliary variable as u ωi , there is an equation as below:…”

“…And recently, the droop control is a method that is most commonly used for the control of inverters in the islanded micro‐grid. But when using this method, there is also a biggest problem: The obtained output frequency and voltages of the controlled DERs are not the reference values . Therefore, the secondary control is usually required to adjust the output frequency and voltages of DERs again .…”

A Hybrid Constraints Handling Strategy for Multiconstrained Multiobjective Optimization Problem of Microgrid Economical/Environmental Dispatch

“…Therefore, the forecast load demands and the predicted environmental data should be obtained first. Besides, the structure and the operation mode of the MG may also change [26,27] according to the operators' requirement, which would cause the change in the optimization models. So the optimization objectives and constraints should also be updated before applying the optimization algorithm.…”