Smart energy management and power flow control for multi-microgrids interfacing with utility grid

Nowadays, new trends have made possible to reconfigure the traditional power systems in a more efficient way while world energy consumption is being continuously increased. To meet future energy demands, a more flexible, smart and configurable power system is required. To create such systems, microgrids are emerging and becoming a more attractive solution. The microgrid is a weak grid formed with different energy sources (renewable and conventional), energy storages, power electronics, power control systems and different loads. The microgrids are also particularly suitable for communities and regions where adequate renewable energy sources are available such as in Qatar. Therefore, the energy cost can be significantly decreased, energy security ensured, and energy production become environmental friendly with lower carbon footprints.

The energy sources are the major part of the microgrid systems. As a result of increasing environmental awareness and as a consequence of the exhaustible nature of fossil fuels, renewable energy sources (RES) are playing an important role in modern microgrid systems. The RES based power generation systems have several advantages compared to the conventional power generation systems. Some of these advantages are sustainability, pollution-free operation and the possibility of being installed closer to the end users. In the last decades, especially the wind and photovoltaic (PV) based power generation systems have become more popular than other RESs. However, intermittent and stochastic nature of the wind and solar affect the stability, reliability and power quality of the microgrids. For instance, the PV based system cannot produce energy at night or during cloudy conditions, and wind-based systems generate energy that depends on the wind condition. To overcome these limitations, two or more (hybrid) RES, in addition to proper storage technologies, are needed to provide reliable, stable and continuous power to the customers. However, using different types of renewable energy sources in the same microgrid leads to complex control structure because these sources have different dynamic characteristics and need different control structures. Hence, a well-designed energy management and power flow control systems are essential to ensure the extraction of maximum power from these energy sources.