However, there are still several issues such as microgrid stability, power and energy management, reliability and power quality that make microgrids implementation challenging. Nevertheless, the energy storage system is proposed as a promising solution to overcome the aforementioned challenges.
3 School of Control and Computer Engineering, North China Electric Power University, Beijing 102206, China 4 Department of Energy Technology at Aalborg University, Denmark Liu X, Zhao T, Deng H, et al. Microgrid Energy Management with Energy Storage Systems: A Review.
The island operation mode of microgrids is based on the energy storage system . At the first level the control tasks during this mode of operation are to regulate the voltage and to maintain the frequency at the constant value.
Distributed energy sources within a microgrid, such as solar photovoltaic modules, wind turbines, and fuel cells, generate DC power or variable frequency AC power. Thus, in microgrids, single- and three-phase inverters are becoming natural components as interfaces for distributed energy sources.
Generally speaking, a controllable electric entity that contains different loads into distributed energy resources form a microgrid . All typical microgrids use two or more sources by which electricity is generated, at least one of which is a renewable source.
In case of any malfunction in the power grid other than the routine operation, the microgrid is separated from the power grid and switched to the isolated (off-grid) mode of operation, and thus, local loads can continue their operation ( Justo et al., 2013 ).