Stability Analysis and Comparison of DC Power System with Different Droop Control Methods

Abstract

With the rapid development of renewable energy system, de power system has been widely applied to accommodate multiple renewable energy sources and power electronic loads, where the voltage source converters (VSCs) are commonly adopted as interconnected interface. The power electronic characteristic of VSCs will bring in stability issues, while the impedance-based stability theory can be used to analyze system stability. In the dc power system, droop control method is widely adopted to coordinate different renewable energy sources, where the droop gain and control structure of droop-controlled VSCs will both affect system stability. This paper mainly focuses on the stability issue in droop-controlled dc power system, and investigates the impacts of droop gain and different control methods based on the developed impedance model. Furthermore, the validity of stability analysis results is further verified through the simulation results.