Stability Analysis and Impedance Specifications of Grid-Connected DC Distribution Power Systems

Impedance-based methods are widely used and recognized for small-signal stability analysis of power-electronics-based power systems. However, the existing stability criteria for complex systems always aggregate all equipment/subsystem impedances. As a result, it is difficult to determine the impedance specification that each equipment/subsystem should meet to ensure system stability and a certain stability margin. In this paper, the stability analysis method for grid-connected dc distribution power systems is first proposed. Then, the port impedance specification of each converter is proposed for the system stability design. As long as all converters meet the proposed impedance specifications, the whole system must be stable and has sufficient stability margin. Finally, the case studies and experiments validate the proposed impedance specifications.