Sampling Aliasing Analysis for Parallel Grid-Tie Inverters Based on Frequency-Domain Model

A microgrid usually contains a large amount of power electronic inverters, the interaction of these inverters can introduce a series of system instability and power quality issues. Inverter is a common power electronic inverters in the microgrid, investigations on the influence between sampling frequency and switching frequency are also not expanded. In fact, when the outputs of multiple inverters are connected in parallel, due to the differences of their switching frequencies and sampling frequencies, the interaction of them can introduce beat frequency oscillation in low frequency regions, even the differences are small. In this paper, a parallel grid-tied inverters model based on sampling aliasing in frequency-domain is developed to predict the beat frequency oscillation in low frequency region.