6,223 research outputs found

    Intelligent Power Control of DC Microgrid

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    An Algorithm for the Efficient Management of the Power Converters Connected to the DC Bus of a Hybrid Microgrid Operating in Grid-connection Mode

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    [EN] In this paper a centralized control strategy for the efficient power management of the power converters conforming a hybrid distributed generation microgrid is explained. The microgrid is based on a DC and an AC bus. The study is focused on the converters connected to the DC bus. The proposed power management algorithm is implemented in a microgrid central processor. This algorithm is based on assigning several operation functions to each of the generators, loads and energy storage systems in the microgrid. A communication system is used to assign the operation functions to each of the microgrid elements. The power flows between the DC and AC buses are studied in several operation scenarios, in which the proposed control can be verified. Experimental and simulation results demonstrate that the algorithm allows to control the power dispatch inside the microgrid properly, by performing the following tasks: (1) the communications among power converters, the grid operator and intelligent loads, (2) the connection and disconnection of loads, (3) the control of the power exchange between the distributed generators and the energy storage system, (4) the compliance of the power dispatch limit set by the grid operator, (5) the synchronization with the grid and (6) the control of the voltage at the DC bus.This work has been cofinanced by the Spanish Ministry of Economy and Competitiveness (MINECO) and by the European Regional Development Fund (ERDF) under Grant ENE2015-64087-C2-2.Salas-Puente, RA.; Marzal-Romeu, S.; González-Medina, R.; Figueres Amorós, E.; Garcerá, G. (2018). An Algorithm for the Efficient Management of the Power Converters Connected to the DC Bus of a Hybrid Microgrid Operating in Grid-connection Mode. Electric Power Components and Systems. On line. https://doi.org/10.1080/15325008.2018.1469177SOn lin

    Experimental Study of a Centralized Control Strategy of a DC Microgrid Working in Grid Connected Mode

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    [EN] The results concerning the integration of a set of power management strategies and serial communications for the efficient coordination of the power converters composing an experimental DC microgrid is presented. The DC microgrid operates in grid connected mode by means of an interlinking converter. The overall control is carried out by means of a centralized microgrid controller implemented on a Texas Instruments TMS320F28335 DSP. The main objectives of the applied control strategies are to ensure the extract/inject power limits established by the grid operator as well as the renewable generation limits if it is required; to devise a realistic charging procedure of the energy storage batteries as a function of the microgrid status; to manage sudden changes of the available power from the photovoltaic energy sources, of the load power demand and of the power references established by the central controller; and to implement a load shedding functionality. The experimental results demonstrate that the proposed power management methodology allows the control of the power dispatch inside the DC microgrid properly.This work has been cofinanced by the Spanish Ministry of Economy and Competitiveness (MINECO) and by the European Regional Development Fund (ERDF) under Grant ENE2015-64087-C2-2.Salas-Puente, RA.; Marzal-Romeu, S.; González-Medina, R.; Figueres Amorós, E.; Garcerá, G. (2017). Experimental Study of a Centralized Control Strategy of a DC Microgrid Working in Grid Connected Mode. Energies. 10(10):1-25. https://doi.org/10.3390/en10101627S1251010Baek, J., Choi, W., & Chae, S. (2017). Distributed Control Strategy for Autonomous Operation of Hybrid AC/DC Microgrid. Energies, 10(3), 373. doi:10.3390/en10030373Patrao, I., Figueres, E., Garcerá, G., & González-Medina, R. (2015). Microgrid architectures for low voltage distributed generation. Renewable and Sustainable Energy Reviews, 43, 415-424. doi:10.1016/j.rser.2014.11.054Ma, T., Yahoui, H., Vu, H., Siauve, N., & Morel, H. (2017). A Control Strategy of DC Building Microgrid Connected to the Neighborhood and AC Power Network. Buildings, 7(4), 42. doi:10.3390/buildings7020042Lin, P., Wang, P., Xiao, J., Wang, J., Jin, C., & Tang, Y. (2018). An Integral Droop for Transient Power Allocation and Output Impedance Shaping of Hybrid Energy Storage System in DC Microgrid. IEEE Transactions on Power Electronics, 33(7), 6262-6277. doi:10.1109/tpel.2017.2741262Kakigano, H., Miura, Y., & Ise, T. (2010). Low-Voltage Bipolar-Type DC Microgrid for Super High Quality Distribution. IEEE Transactions on Power Electronics, 25(12), 3066-3075. doi:10.1109/tpel.2010.2077682Salomonsson, D., Soder, L., & Sannino, A. (2008). An Adaptive Control System for a DC Microgrid for Data Centers. IEEE Transactions on Industry Applications, 44(6), 1910-1917. doi:10.1109/tia.2008.2006398Xu, L., & Chen, D. (2011). Control and Operation of a DC Microgrid With Variable Generation and Energy Storage. IEEE Transactions on Power Delivery, 26(4), 2513-2522. doi:10.1109/tpwrd.2011.2158456Nejabatkhah, F., & Li, Y. W. (2015). Overview of Power Management Strategies of Hybrid AC/DC Microgrid. IEEE Transactions on Power Electronics, 30(12), 7072-7089. doi:10.1109/tpel.2014.2384999Lu, X., Guerrero, J. M., Sun, K., & Vasquez, J. C. (2014). An Improved Droop Control Method for DC Microgrids Based on Low Bandwidth Communication With DC Bus Voltage Restoration and Enhanced Current Sharing Accuracy. IEEE Transactions on Power Electronics, 29(4), 1800-1812. doi:10.1109/tpel.2013.2266419Chen, D., & Xu, L. (2012). Autonomous DC Voltage Control of a DC Microgrid With Multiple Slack Terminals. IEEE Transactions on Power Systems, 27(4), 1897-1905. doi:10.1109/tpwrs.2012.2189441Guerrero, J. M., Vasquez, J. C., Matas, J., de Vicuna, L. G., & Castilla, M. (2011). Hierarchical Control of Droop-Controlled AC and DC Microgrids—A General Approach Toward Standardization. IEEE Transactions on Industrial Electronics, 58(1), 158-172. doi:10.1109/tie.2010.2066534Vasquez, J., Guerrero, J., Miret, J., Castilla, M., & Garcia de Vicuna, L. (2010). Hierarchical Control of Intelligent Microgrids. IEEE Industrial Electronics Magazine, 4(4), 23-29. doi:10.1109/mie.2010.938720Unamuno, E., & Barrena, J. A. (2015). Hybrid ac/dc microgrids—Part II: Review and classification of control strategies. Renewable and Sustainable Energy Reviews, 52, 1123-1134. doi:10.1016/j.rser.2015.07.186Feng, X., Shekhar, A., Yang, F., E. Hebner, R., & Bauer, P. (2017). Comparison of Hierarchical Control and Distributed Control for Microgrid. Electric Power Components and Systems, 45(10), 1043-1056. doi:10.1080/15325008.2017.1318982Kaur, A., Kaushal, J., & Basak, P. (2016). A review on microgrid central controller. Renewable and Sustainable Energy Reviews, 55, 338-345. doi:10.1016/j.rser.2015.10.141Wu, D., Tang, F., Dragicevic, T., Guerrero, J. M., & Vasquez, J. C. (2015). Coordinated Control Based on Bus-Signaling and Virtual Inertia for Islanded DC Microgrids. IEEE Transactions on Smart Grid, 6(6), 2627-2638. doi:10.1109/tsg.2014.2387357Shi, D., Chen, X., Wang, Z., Zhang, X., Yu, Z., Wang, X., & Bian, D. (2018). A Distributed Cooperative Control Framework for Synchronized Reconnection of a Multi-Bus Microgrid. IEEE Transactions on Smart Grid, 9(6), 6646-6655. doi:10.1109/tsg.2017.2717806Dou, C., Zhang, Z., Yue, D., & Zheng, Y. (2017). MAS-Based Hierarchical Distributed Coordinate Control Strategy of Virtual Power Source Voltage in Low-Voltage Microgrid. IEEE Access, 5, 11381-11390. doi:10.1109/access.2017.2717493Bracale, A., Caramia, P., Carpinelli, G., Mancini, E., & Mottola, F. (2015). Optimal control strategy of a DC micro grid. International Journal of Electrical Power & Energy Systems, 67, 25-38. doi:10.1016/j.ijepes.2014.11.003Yue, J., Hu, Z., Li, C., Vasquez, J. C., & Guerrero, J. M. (2017). Economic Power Schedule and Transactive Energy through an Intelligent Centralized Energy Management System for a DC Residential Distribution System. Energies, 10(7), 916. doi:10.3390/en10070916Gao, L., Liu, Y., Ren, H., & Guerrero, J. (2017). A DC Microgrid Coordinated Control Strategy Based on Integrator Current-Sharing. Energies, 10(8), 1116. doi:10.3390/en10081116Operating Instructions Valve Regulated Stationary Lead-Acid Batterieshttp://www.hoppecke-us.com/tl_files/hoppecke/Documents/HO-US/Operating_Instructions_sealed_stationary_lead_acid_batteries_en1111.pdfTAB Batterieshttp://www.tabspain.com/wp-content/uploads/informacion-tecnica/renovables/curvas-y-tablas/din-41773-y-din-41774-para-baterias-pzs.pdfZhao, J., & Dörfler, F. (2015). Distributed control and optimization in DC microgrids. Automatica, 61, 18-26. doi:10.1016/j.automatica.2015.07.015Eghtedarpour, N., & Farjah, E. (2014). Power Control and Management in a Hybrid AC/DC Microgrid. IEEE Transactions on Smart Grid, 5(3), 1494-1505. doi:10.1109/tsg.2013.2294275Installation, Commissioning and Operation Handbook for Gel-Vrla-Batterieshttp://www.sonnenschein.org/PDF%20files/GelHandbookPart2.pdfAlLee, G., & Tschudi, W. (2012). Edison Redux: 380 Vdc Brings Reliability and Efficiency to Sustainable Data Centers. IEEE Power and Energy Magazine, 10(6), 50-59. doi:10.1109/mpe.2012.2212607Aryani, D., & Song, H. (2016). Coordination Control Strategy for AC/DC Hybrid Microgrids in Stand-Alone Mode. Energies, 9(6), 469. doi:10.3390/en9060469Dragicevic, T., Guerrero, J. M., Vasquez, J. C., & Skrlec, D. (2014). Supervisory Control of an Adaptive-Droop Regulated DC Microgrid With Battery Management Capability. IEEE Transactions on Power Electronics, 29(2), 695-706. doi:10.1109/tpel.2013.2257857Tian, Y., Li, D., Tian, J., & Xia, B. (2017). State of charge estimation of lithium-ion batteries using an optimal adaptive gain nonlinear observer. Electrochimica Acta, 225, 225-234. doi:10.1016/j.electacta.2016.12.119Standard for Interconnecting Distributed Resources with Electric Power Systemshttp://fglongatt.org/OLD/Archivos/Archivos/SistGD/IEEE1547.pd

    Exploring Cyber Security Issues and Solutions for Various Components of DC Microgrid System

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    Nowadays, considering the growing demand for the DC loads and simplified interface with renewable power generation sources, DC microgrids could be cost effective solution for the power supply in small scale area. the supervisory control and data acquisition (SCADA) system maintain the bidirectional power communication through the internet connectivity with the microgrid. However, this intelligent and interactive feature may pose a cyber-security threat to the power grid. this work aims to exploring cyber-security issues and their solutions for the DC microgrid system. To mitigate the adverse effects of various cyber-attacks such as the False Data Injection (FDI) attack, Distributed Denial of Service (DDoS) attack etc., two new techniques based on non-linear and proportional-integral (PI) controllers have been proposed. Simulation results obtained from MATLAB/Simulink software demonstrate the effectiveness of the proposed methods in mitigating the adverse effects of cyber-attacks on the DCMG system performance

    Modeling and Control of Low-Voltage DC Microgrid With Photovoltaic Energy Resources

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    The use of DC microgrids is a promising concept that could improve power system reliability and stability in the future. The advantages of microgrids in general include an increase in energy efficiency through lowered energy transmission and operational costs, a reduced carbon footprint through the integration of renewable energy resources, and improvements in power quality and availability to end users through the use of advanced control techniques. DC microgrids have the potential to provide additional advantages, including decreasing interconnection conversion levels of distributed energy resources and energy storage systems, and preventing the propagation of power system disturbances. Power system research groups around the world are investigating the DC microgrid concept through simulation platforms and experimental setups. Several strategies have been proposed for the control of DC microgrids, including hierarchical, distributed, and intelligent control strategies. In this work, PSCAD/EMTDC simulation environment was used for the modeling and simulation of a DC microgrid. A power management strategy was then implemented in order to ensure voltage regulation and seamless transition between grid-connected and isolated modes. The strategy is based on an autonomous distributed control scheme in which the DC bus voltage level is used as an indicator of the power balance in the microgrid. The autonomous control strategy does not rely on communication links or a central controller, resulting in reduced costs and enhanced reliability. As part of the control strategy, an adaptive droop control technique is proposed for PV sources in order to maximize the utilization of power available from these sources while ensuring acceptable levels of system voltage regulation. These goals are achieved by avoiding the curtailment of renewable energy until violation of the voltage regulation limit occurs. The adaptive droop control then curtails the output power of the PV sources and, at the same time, restores the DC voltage level to within an acceptable tolerance range

    Modeling and Control of Low-Voltage DC Microgrid With Photovoltaic Energy Resources

    Get PDF
    The use of DC microgrids is a promising concept that could improve power system reliability and stability in the future. The advantages of microgrids in general include an increase in energy efficiency through lowered energy transmission and operational costs, a reduced carbon footprint through the integration of renewable energy resources, and improvements in power quality and availability to end users through the use of advanced control techniques. DC microgrids have the potential to provide additional advantages, including decreasing interconnection conversion levels of distributed energy resources and energy storage systems, and preventing the propagation of power system disturbances. Power system research groups around the world are investigating the DC microgrid concept through simulation platforms and experimental setups. Several strategies have been proposed for the control of DC microgrids, including hierarchical, distributed, and intelligent control strategies. In this work, PSCAD/EMTDC simulation environment was used for the modeling and simulation of a DC microgrid. A power management strategy was then implemented in order to ensure voltage regulation and seamless transition between grid-connected and isolated modes. The strategy is based on an autonomous distributed control scheme in which the DC bus voltage level is used as an indicator of the power balance in the microgrid. The autonomous control strategy does not rely on communication links or a central controller, resulting in reduced costs and enhanced reliability. As part of the control strategy, an adaptive droop control technique is proposed for PV sources in order to maximize the utilization of power available from these sources while ensuring acceptable levels of system voltage regulation. These goals are achieved by avoiding the curtailment of renewable energy until violation of the voltage regulation limit occurs. The adaptive droop control then curtails the output power of the PV sources and, at the same time, restores the DC voltage level to within an acceptable tolerance range

    Integration of AC/DC Microgrids into Power Grids

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    AC/DC Microgrids are a small part of low voltage distribution networks that are located far from power substations, and are interconnected through the point of common coupling to power grids. These systems are important keys for the flexible, techno-economic, and environmental-friendly generation of units for the reliable operation and cost-effective planning of smart electricity grids. Although AC/DC microgrids, with the integration of renewable energy resources and other energy systems, such as power-to-gas, combined heat and power, combined cooling heat and power, power-to-heat, power-to-vehicle, pump and compressed air storage, have several advantages, there are some technical aspects that must be addressed. This Special Issue aims to study the configuration, impacts, and prospects of AC/DC microgrids that enable enhanced solutions for intelligent and optimized electricity systems, energy storage systems, and demand-side management in power grids with an increasing share of distributed energy resources. It includes AC/DC microgrid modeling, simulation, control, operation, protection, dynamics, planning, reliability and security, as well as considering power quality improvement, load forecasting, market operations, energy conversion, cyber/physical security, supervisory and monitoring, diagnostics and prognostics systems
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