This paper proposes a new structure and control scheme for future microgrid-based power system, which is designed to achieve a seamless operation in both islanded and grid-connected modes, while the load is appropriately shared by all units (i.e., renewable sources, energy storage systems and the grid). The proposed method, which involves physical separation of the microgrid from the grid by using AC/DC/AC converters, ensures safe, secure and seamless operation of both modes. Such a “buffered” structure enables reduction in the transmission losses by reducing the exchanged energy with the grid through using a dead-zone in the control of the buffering AC/DC/AC converter. An inverse-droop control technique has been implemented to control the voltage magnitude and frequency, using current control in the dq -frame. PSCAD/EMTDC software has been used to validate the proposed method through simulating different scenarios. The solution provides a simple, smooth, and communication-free decentralized control for multi-sources microgrids. Moreover, the proposed buffered structure separates the dynamics of the microgrid and the grid, which enables a faster microgrid voltage and frequency control and protects the grid and the microgrid from faults on the other side.

中文翻译：

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未来电网的微网缓冲结构；无缝微电网控制

本文为未来的基于微电网的电力系统提出了一种新的结构和控制方案，旨在在孤岛和并网模式下实现无缝运行，同时负载由所有单元（即可再生能源，能源存储系统和网格）。所提出的方法涉及通过使用AC / DC / AC转换器将微电网与电网物理隔离，从而确保两种模式的安全，安全和无缝运行。这种“缓冲”结构通过在缓冲AC / DC / AC转换器的控制中使用死区来减少与电网的交换能量，从而能够减少传输损耗。反向降压控制技术已经实现，它可以通过使用电流控制中的电流控制来控制电压幅度和频率。dq -帧。PSCAD / EMTDC软件已用于通过模拟不同的场景来验证所提出的方法。该解决方案为多源微电网提供了一种简单，平稳且无通信的分散控制。而且，所提出的缓冲结构将微电网和电网的动力学分开，这使得能够更快地控制微电网的电压和频率，并保护电网和微电网免受另一侧的故障的影响。