A DC power system stabilizer based on passivity-oriented DC bus impedance shaping

High penetration of Power Electronic (PE) converters in DC power grids causes new stability challenges due to dynamic interactions among the subsystems of a network. Such dynamic interactions can be avoided by the impedance coordination among the subsystems through the modification of control loops or passive elements inside a grid. Impedance coordination is a very complex and time-consuming task with no adaptations to dynamic changes in a power grid. The current study delved into the concepts of dynamic interaction and passivity and they were combined to provide an online stability measure concerning the DC bus impedance characteristics. In this regard, a novel DC Power System Stabilizer (PSS) was proposed, which was connected to a DC bus as a separate module passivizing the bus impedance at non-passive interaction frequencies. The interaction frequencies were detected through a broadband online identification process. The PSS working principle, topology, modeling, and control designs were also discussed in detail. Finally, the functionality and performance of the proposed stabilizer were validated by the simulation results.