Decentralized Impedance Specifications for Small-Signal Stability of DC Distributed Power Systems

Currently, the scale of dc distributed power systems (DPSs) is experiencing a sustained high-speed growth, which makes stability analysis become a complicated but essential problem. This paper has proposed decentralized impedance specifications for small-signal stability of a dc DPS which contains one voltage source subsystem, multiple power controlled source subsystems and multiple load subsystems. The proposed method defines invariant impedance specifications for each subsystem of the DPS, which only depend on the rated dc bus voltage and the rated capacity of each subsystem. The decentralized invariant impedance specifications make it possible that each subsystem is designed individually and the small-signal stability of the DPS is guaranteed at the same time. The proposed method can be applied to both large-scale and plug-and-play dc DPSs, whose stability analyses with conventional approaches would suffer from the curse of dimensionality and changing parameters. The proposed method is verified by hardware-in-loop tests.