Fuzzy-PI Controllers for Grid-Connected and Islanded Operation of DG in a Microgrid (original) (raw)

IJERT-Fuzzy-PI Controllers for Grid-Connected and Islanded Operation of DG in a Microgrid

International Journal of Engineering Research and Technology (IJERT), 2013

https://www.ijert.org/fuzzy-pi-controllers-for-grid-connected-and-islanded-operation-of-dg-in-a-microgrid https://www.ijert.org/research/fuzzy-pi-controllers-for-grid-connected-and-islanded-operation-of-dg-in-a-microgrid-IJERTV2IS100110.pdf Islanding describes the condition in which a microgrid or a portion of the power grid, which consists of a load and a distributed generation (DG) system, is isolated from the remainder of the utility system. In

Analysis of Fuzzy Inference Power Control Strategies for Islanding Operation of Microgrids

Microgrid is a latest notion for future energy distribution system that enables renewable energy integration. It generally consists of multiple distributed generators that are usually interfaced to the grid through power inverters. Fuzzy controller is proposed at Distributed Generation (DG) units for the islanding operation of ac microgrids. Two important jobs are to divide up the load demand among multiple parallel connected inverters proportionately, and maintain the voltage and frequency stabilities. Finally, this paper presents the deviation in power and frequency of micro grids with DG Units.

Dynamic modeling of microgrid for grid connected and intentional islanding operation

2012 International Conference on Advances in Power Conversion and Energy Technologies (APCET), 2012

Microgrid is defined as the cluster of multiple distributed generators (DGs) such as renewable energy sources that supply electrical energy. The connection of microgrid is in parallel with the main grid. When microgrid is isolated from remainder of the utility system, it is said to be in intentional islanding mode. In this mode, DG inverter system operates in voltage control mode to provide constant voltage to the local load. During grid connected mode, the Microgrid operates in constant current control mode to supply preset power to the main grid. The main contribution of this paper is summarized as 1) Design of a network based control scheme for inverter based sources, which provides proper current control during grid connected mode and voltage control during islanding mode. 2) Development of an algorithm for intentional islanding detection and synchronization controller required during grid reconnection. 3) Dynamic modeling and simulation are conducted to show system behavior under proposed method using SIMULINK. From the simulation results using Simulink dynamic models, it can be shown that these controllers provide the microgrid with a deterministic and reliable connection to the grid.

Frequency control of islanded microgrid using fuzzy-PI and autotuned controllers

International Journal of Advances in Applied Sciences (IJAAS) , 2019

Any mismatch between generation and demand causes frequency to deviate from nominal value which affects the microgrid operation and reliability of power flow. The load frequency changes abnormally, which is fuzzy in nature, due to low system inertia and unpredictable variation in wind and solar irradiance level. So a frequency controller is needed to solve this problem meeting generation and demand of an islanded microgrid system considering the fuzziness in frequency fluctuation. This paper presents a case study of a hybrid microgrid system consisting of PV system, wind turbine generator set, diesel generator set along with storage facility and equipped with a proposed fuzzy-PI controller for frequency control under islanded condition. This controller shows satisfactory steady-state response. Further, performance of the proposed fuzzy-PI controller is verified with that of an autotuned PI controller to get faster response. The change in frequency is found minimum in case of autotuned PI controller as compared to fuzzy-PI controller. The proposed fuzzy-PI controller is validated based on ITAE (4-7%) which is higher than that attained form autotuned-PI controller. The developed model is simulated in Matlab/Simulink environment in this case study.

Grid voltage control in islanded microgrids with inverter-interfaced power sources

2nd Innovation for Sustainable Production conference (i-SUP 2010), 2010

The increased amount of distributed generation units connected to the distribution network has led to the development of the microgrid, which can operate in grid-connected or islanded mode. In the islanded microgrid, the mostly inverter-interfaced power sources are responsible for both voltage and power control. Therefore, adequate control algorithms for the microgrid inverters have to be developed. In this paper, an active power / grid voltage droop control strategy is applied for the power control. It is introduced as an outer control loop that determines the set-value of the inner grid voltage control loop. The grid voltage control is performed with different control strategies that are compared in steady-state and in worst-case circumstances. It is shown that the PI and fuzzy logic controller show the best overall performance in the microgrid application.

Control for Grid-Connected and Intentional Islanding Operations of Distributed Power Generation

IEEE Transactions on Industrial Electronics, 2011

Intentional islanding describes the condition in which a microgrid or a portion of the power grid, which consists of a load and a distributed generation (DG) system, is isolated from the remainder of the utility system. In this situation, it is important for the microgrid to continue to provide adequate power to the load. Under normal operation, each DG inverter system in the microgrid usually works in constant current control mode in order to provide a preset power to the main grid. When the microgrid is cut off from the main grid, each DG inverter system must detect this islanding situation and must switch to a voltage control mode. In this mode, the microgrid will provide a constant voltage to the local load. This paper describes a control strategy that is used to implement grid-connected and intentional-islanding operations of distributed power generation. This paper proposes an intelligent load-shedding algorithm for intentional islanding and an algorithm of synchronization for grid reconnection.

Design of Controller for Transition of Grid Connected Microgrid to Island Mode

2021

A microgrid is the combination of Distributed generators that interconnected with the main grid to ensure continuity in supply to the load. The operating system will be in grid-connected and the island mode. This paper presents a mathematical model of hybrid microgrid consisting of PV system, wind power generation using DFIG which are integrated to the utility grid and a PI Controller for controlling the transition from grid-connected mode to island mode and normal operation, each DG inverter sated in constant current control mode to provide preset power to the main grid. When it disconnects from the main grid each DG inverter detects and connect to voltage control mode in the islanding situation. The modeling is performed in MATLAB Simulink and results are discussed out to verify the operation of the proposed system .

Intelligent Power Management of Islanded DC Microgrid based on Droop Fuzzy Control

— This paper presents a new intelligent control strategy for DC microgrid in islanded operation mode based on droop control method. The DC microgrid under study included a Wind Turbine Generator (WTG), photovoltaic (PV), battery energy storage system (BESS) and a linear resistive load. According to the proposed method, each of distributed generation (DG) sources and BESS can be deployed independently within any controlled microgrid through the fuzzy control strategy. Proposed fuzzy control regulated virtual resistance of DGs and BESS unit locally and real-time based on the available power of DGs and the battery state of charge (SOC), to coordinate the module performances independently and establish the power balance and regulating DC bus voltage. Proposed control strategy for BESS enables the microgrid to supply independently the power required for the load demand when the DGs are not capable of supplying the required power to the load. The proposed fuzzy control strategy was applied locally and without dependency on the telecommunication links or any centralized energy management system. In order to validate the proposed method, the control system was implemented on a DC microgrid within MATLAB/SIMULINK, where the simulation results were analyzed and validated. Keywords—DC microgrid, fuzzy inferencesystem (FIS), droop method, decentralized control, islanded operation.

A fuzzy-based approach for microgrids islanded operation

Electric Power Systems Research, 2017

Power system blackouts harm economic activities and worsen the customers' welfare. Smart grids' selfhealing capacity is an important feature for future power systems and it should also include the ability to manage the distributed energy resources to ensure power supply for a longer time. This is required because the duration of a blackout is unknown and bulk power system blackstart is a complex task. The deployment of microgrids can overcome these challenges since they may be operated in an autonomous way. This paper proposes a methodology for microgrid management in islanded conditions aiming to maximize the duration of power supply taking into account the availability of renewable sources and stored energy. In order to accomplish this goal, some management options are considered, such as load shedding, dispatch of expensive fossil fuel sources, and demand response actions. The control actions are determined with the help of a fuzzy logic methodology. The proposed approach is validated with a modified IEEE 34 node sample system.

Managing the Distributed Generation Units in a Microgrid using a Fuzzy-PI Controller

Przegląd Elektrotechniczny, 2015

A power distribution system with distributed generations can operate as a microgrid under specific conditions. A microgrid can be operated under grid-connected and islanded modes seamlessly without disrupting the loads within the microgrid. This study analyzes the intelligent control of a microgrid with a pulse-width modulation-controlled voltage source inverter. Switching patterns are generated through a fuzzy proportional-integral (PI) controller. This study aims to develop a fuzzy-PI controller and compare its performance with that of a PI controller in controlling the voltage and frequency of a microgrid under disturbances in a Matlab/Simulink environment. Results show that the fuzzy-PI controller has higher capability, precision, and robustness than the PI controller in quickly restoring and stabilizing the microgrid. A simulation experiment is also performed to verify the greater validity and effectiveness of the microgrid equipped with the fuzzy-PI controller than with the PI controller. The developed fuzzy-PI controller can reduce the total harmonic distortion by 0.46%. Streszczenie. W artykule analizowano inteligentne sterowanie mikrosieci z wykorzystaniem przekszta tnika sterowanego metod modulacji szeroko ci impulsu. Jako sterownik wykorzystano proporcjonalno ca kuj cy uk ad z logika rozmyt. Zbadano prac uk adu w sieci z zak óceniami. Stwierdzon znacz ce przewagi kontrolera pracuj cego z logika rozmyt w porównaniu do uk adów konwencjonalnvch. Zarz dzanie rozproszonymi generatorami w mikrocieci z wykorzystaniem sterowników o logice rozmytej