Distributed Secondary Voltage and Frequency Control for Islanded Microgrids With Uncertain Communication Links

• Published in: IEEE transactions on industrial informatics Vol. 13; no. 2; pp. 448 - 460
• Main Authors: Xiaoqing Lu, Xinghuo Yu, Jingang Lai, Guerrero, Josep M., Hong Zhou
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.04.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Active control; Communication; Communications systems; Control stability; Controllers; Density estimation robust algorithm; Discrete-time; distributed control; Distributed generation; Electric potential; Electric power grids; Energy sources; Frequency control; Frequency measurement; Graph theory; Informatics; islanded microgrid; Restoration; Robust control; secondary control; Stability analysis; System reliability; Systems stability; Voltage control; Voltage measurement
• ISSN: 1551-3203; 1941-0050
• DOI: 10.1109/TII.2016.2603844

This paper presents a robust distributed secondary control (DSC) scheme for inverter-based microgrids (MGs) in a distribution sparse network with uncertain communication links. By using the iterative learning mechanics, two discrete-time DSC controllers are designed, which enable all the distributed energy resources (DERs) in an MG to achieve the voltage/frequency restoration and active power sharing accuracy, respectively. In special, the secondary control inputs are merely updated at the end of each round of iteration, and thus, each DER only needs to share information with its neighbors intermittently in a low-bandwidth communication manner. This way, the communication costs are greatly reduced, and some sufficient conditions on the system stability and robustness to the uncertainties are also derived by using the tools of Lyapunov stability theory, algebraic graph theory, and matrix inequality theory. The proposed controllers are implemented on local DERs, and thus, no central controller is required. Moreover, the desired control objective can also be guaranteed even if all DERs are subject to internal uncertainties and external noises including initial voltage and/or frequency resetting errors and measurement disturbances, which then improves the system reliability and robustness. The effectiveness of the proposed DSC scheme is verified by the simulation of an islanded MG in MATLAB/SimPowerSystems.