Small-signal stability analysis of integrated VSC-based DC/AC power systems - A review

The voltage source converters (VSCs) are the most important dynamic components in a VSC-based DC/AC power system. The renewable power generation, VSC-based HVDC lines and multi-terminal DC (MTDC) network are connected to the AC power system via the VSCs. This paper reviews the recent main research progress and conclusions on the small-signal stability of the VSC-based DC/AC power system. The review covers the study on the small-signal stability of a grid-connected single VSC system, an integrated VSC-HVDC/AC power system and the MTDC/AC power system. It is explained in the paper why the study so far on the small-signal stability of the VSC-based DC/AC power system has been focused on examining the dynamic interactions between the converter control and the phase locked loop (PLL), between the multiple VSCs as well as between the VSCs and synchronous generators (SGs). The paper is concluded by summarizing the main factors affecting the small-signal stability of the VSC-based DC/AC power system. Gaps of study are listed and analyzed to call upon further investigation in order to fully reveal the mechanism about why the VSC-based DC/AC power system may loss the small-signal stability.