To achieve a more sustainable supply of electricity, consumers are expected to rely increasingly on combinations of various types of power generators. Among them, distributed generators (DGs) utilizing renewable energy sources (RESs) are a promising solution. However, introducing renewable energy based DGs into microgrids (MGs) can reduce the inertia of the whole power system, and hence, the system frequency and the voltage can be fluctuated. Furthermore, unnecessary interference occurs as the number of synchronous machines increases. To address these issues, it is desirable to develop a noble inverter control method for DGs, and to gain an intuitive understanding of the dynamic characteristics of MG power systems. In this paper, the impacts of frequency/voltage deviations in MGs are mathematically investigated using algebraic-type virtual synchronous generator (VSG). The algebraic-type VSG with a minimal number of parameters has an ability to suppress the system frequency and voltage deviations. The proposed control approach presents a suitable solution for penetration of more and more renewable energy into the existing power grids. The results of the analysis were verified via simulations and experiments.
