Study of Voltage Oscillation in Multi-Converter Based DC Microgrid

This paper presents the impact of various disturbances in the multi converter-based DC microgrid. Source, load, and the contingency on both side have been considered for this investigation. It is found that disturbances can potentially deteriorate the controller performance and contribute to oscillation and resonance at DC bus. In this investigation, a small-scale multi converter-based DC microgrid is designed first, and case studies have been conducted with the traditional single-variable controller. Three methodologies including impedance scanning, fast Fourier transform (FFT) analysis, and time-domain simulation have been applied concurrently to check the small-signal stability on DC bus in DC microgrid. It is noticed that the disturbances at the same time on the source and load side are more influential than the single side disturbance. Besides, source-side voltage disturbance is also appearing significant, considered to the load disturbances. This analysis framework would help a researcher/planner in designing a stable multi converter-based DC microgrid.