Design, analysis, and comparison of inverter control methods for microgrid application for stand-alone sites

The increasing awareness of the need to reduce pollution and global warming, and the increasing price of conventional energy resources, encouraged many countries to adapt new energy policies by including renewable energy resources, such as solar energy, wind energy, tidal energy. These new energy sources are usually connected to the gird via inverters, which presents fast dynamics due to their small output impedance. Such fast dynamics systems can contribute to voltage and frequency variations. These variations could be problematic in the particular case of stand-alone sites in absence of a main grid that could help regulating the voltage and the frequency. In this paper, a multi-source system for a stand-alone site will be studied under different control strategies. In particular, a power control, a voltage and frequency control, and an inverter virtual synchronous generator control strategies are adopted and evaluated. Afterwards, two specific multi-source control strategies, namely the traditional droop control and a virtual synchronous generator control, are simulated and evaluated based on a comparative study.