Distributed secondary voltage regulation for autonomous microgrid

© 2017 IEEE. This research addresses the control problem of microgrids and presents a robust distributed secondary control system for voltage regulation of an islanded microgrid with droop-controlled and inverter-based distributed generators (DGs). A consensus-based distributed control approach is proposed to restore the voltage and frequency of the islanded microgrid to the reference values for all DGs within a very short time. The proposed method is flexible to system topology variations which AIDS the plug-and-play operation of microgrid. An autonomous micogrid test system consisting of four DGs is constructed in MATLAB using SimPowerSystem Toolbox to test the proposed design method, and the simulation results show the effectiveness of the proposed control strategy. The performance of the proposed controller is shown through several test case studies

Distributed Control and Power Management Strategy for an Autonomous Hybrid Microgrid with Multiple Sub-Microgrids

This paper proposes a novel approach of distributed coordination control for multiple sub-microgrids (SMGs) within a hybrid AC/DC microgrid. The conventional control approach for managing power flow among AC and DC SMGs is based on the proportional power sharing principle. This is mainly implemented by equalising the normalized voltage at the DC side and the frequency at the AC side for any interfaced SMGs. The proposed method suggests a distributed control system that ensures a total controllability for the interlinking converters. It overcomes the total dependency on a specific variable for power exchange. The proposed method not only enables control of the power flow between SMGs but also ensures the continuity of power transfer if any single SMG fails. Three case studies are presented to demonstrate the validity and capability of the proposed approach using the MATLAB/Simulink software. From the obtained results, it is found that the proposed control system provides a high level of flexibility in managing the power flow among SMGs

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

This research suggests a novel distributed cooperative control methodology for a secondary controller in islanded microgrids (MGs). The proposed control technique not only brings back the frequency/voltage to its reference values, but also maintains precise active and reactive power-sharing among distributed generation (DG) units by means of a sparse communication system. Due to the dynamic behaviour of distributed secondary control (DSC), stability issues are a great concern for a networked MG. To address this issue, the stability analysis is undertaken systematically, utilizing the small-signal state-space linearized model of considering DSC loops and parameters. As the dynamic behaviour of DSC creates new oscillatory modes, an intelligent fuzzy logic-based parameter-tuner is proposed for enhancing the system stability. Accurate tuning of the DSC parameters can develop the functioning of the control system, which increases MG stability to a greater extent. Moreover, the performance of the offered control method is proved by conducting a widespread simulation considering several case scenarios in MATLAB/Simscape platform. The proposed control method addresses the dynamic nature of the MG by supporting the plug-and-play functionality, and working even in fault conditions. Finally, the convergence and comparison study of the offered control system is shown

A novel method for optimizing distributed generation in distribution networks using the game theory

© 2017 IEEE. In this paper, a novel method is presented to optimize distributed generation (DG) in distribution networks. The suggested method shows how DGs should change their sizes and places, if it is necessary, to improve the voltage profile and total power loss of distribution networks. For this purpose, game theory is applied to model the optimization problem. At the first step, an appropriate game based on the Nash equilibrium is suggested. Using the specific features of game theory, the procedure of decision making in the operator centers of distribution grids is considered. Then, the optimization problem is solved by finding Nash equilibrium point. To solve the Nash equilibrium, a specific kind of genetic algorithm (GA) called Nash GA is applied

Power management and control strategy for hybrid AC/DC microgrids in autonomous operation mode

© 2017 IEEE. The hybrid AC/DC microgrid structure is considered to be the future trend of power systems, due to the vital necessity of connecting more renewable energy sources and storage elements to supply modern AC and DC loads. This paper proposes a power sharing and control strategy for hybrid AC/DC microgrids using the droop control technique. A new structure of the hybrid microgrid is suggested by connecting different AC, and DC sub-grids by an interlinking converter. This can be symbolized by a bi-directional converter that acts as a rectifier when power flows from the AC sub-grid to the DC subgrid. And operates as an inverter when power flows from the DC subgrid to the AC one. The proposed structure and power management strategy also allow power flows between DC sides of the system through the AC subgrid as a common bus. Five scenarios of transferring power from one sub-grid to another are studied using. MATLAB/Simulink. The results indicate a high level of the system's felexibility in managing th power flow