Comparative Study of Four Droop Control Strategies in DC Microgrid.

Direct Current (DC) microgrids have the potential to improve efficiency and reliability of power system operations in many applications. A key building block for the stable operation of a DC microgrid is its control strategy. Droop control has been introduced as one of the most popular strategies. However, basic characteristics of different types of droop control have not been fully investigated. While there are a lot of work about the voltage-current (VI) and current-voltage (IV) droop characteristics, analysis of voltage-power (VP) and power-voltage (PV) has not been fully considered and compared. This paper provides the comparative analysis, testing, and performance evaluation of VI, VP, PV, IV droops for the case of a buck converter. The analytical and simulation results provide a picture of similarities and differences among four droops under comparison. Instead of conventional conception of similar VI and VP, as well as IV and PV, their steady state performance and stability assessment results are different.