Research on Large-Signal Stability of DC Microgrid Based on Droop Control

Abstract

Ensuring the large signal stability of the DC microgrid is the premise of the safe operation of the DC microgrid, but the research on the large-signal stability of microgrids with multiple droop control micro-sources is still scarce. In this paper, a DC microgrid system model with multiple droop control micro-sources was established by appropriate simplification. Addressing the problem that most stability research methods cannot be quantitatively analyzed, the mixed potential function method was used to analyze the large signal stability of the system. However, the criterion obtained by the conventional mixed potential function method is complicated and contains multiple time-varying parameters, which is not convenient for analysis. Therefore, the simple form of the criterion was obtained through simplification and the analysis proved the rationality of the simplification. On this basis, a nonlinear droop control method was proposed to improve the anti-interference ability of the system. Finally, the accuracy of the large signal stability criterion and the effectiveness of nonlinear droop control on the system’s large signal stability were verified by simulation.

A comprehensive review of DC microgrid in market segments and control technique

“…In recent times, by coordination between different units in the microgrid, a study of DC Microgrid control, adaptive stability analysis, and stabilization strategies has been introduced, and three major organized control methods are characterized: autonomous, unified, and distributed control. In addition, some major impedance parameters and standards of stability are being reviewed [ 15 ].…”

A Protection System for Improved Ring-Bus DC Microgrids

“…Furthermore, the protection system has its own troubles. At first, in a DC microgrid, there are usually a large number of converters for both the DGs and loads, while the vulnerable power electronics components in converters are only able to bear the overcurrent for less than 10 milliseconds [7,8]. Therefore, the speed requirements for protection are very rigid and not easy to be met.…”