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The aim of this study is to investigate the strategy for the coordinated control of the micro-grid (distributed generation) using various technologies for the power generation, such as wind, photovoltaic source, and energy storage. The coordinated control of the power sources and the energy storage equipment ensures the micro-grid to be much safer, reliable and cost-effective under the different operating conditions. The main research interests are listed below. First, the models for the different distributed power sources (wind, photovoltaic, and micro-turbine) and the energy storage equipment are built according to the theory of mathematics and engineering. The mechanism of the power sources is analyzed and the characters of their output are obtained via the simulation experiment. In addition, the tracking technology for maximum power point tracking(MPPT),and charging and discharging properties of the energy storage equipment (Lithium Ion Battery) are further analyzed. Secondly, the controlling technology and strategy framework for the three different types of the inverter interface, including constant power, voltage and frequency, are analyzed. Furthermore, the current dominating controlling strategy for the micro-grid is introduced, such as constant power control (grid-connected system), the constant voltage and frequency, and droop control. Thirdly, with the analysis of the peer-to-peer, master-slave, and multi-agent and Hierarchical control, the structure and technology of the above three different control models are studied. During the change of the operating conditions, the different power sources are coordinated to ensure that the micro-grid could obtain the sufficient power supply under different working conditions and models. Finally, the investigation of the controlling strategy is adopted by Ping-tung smart micro-grid. The analysis of its existing issues for the optimization is proposed in order to achieve a safe and stable operation and smoothly conversion among the different modes, which leads to ultimate aim of this study, to maximize the usage of the renewable energy and to achieve the more cost-effective solution.
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