A new stability assessment criterion for dc power systems using multi-level virtual conductors

This paper presents a new stability criterion for bidirectional DC-DC converters in a dc power system. Factually, it is so sophisticated to use conventional stability criteria to assess the stability of a dc power system consists of huge number of nodes. The proposed criterion gives an overall indicator for the stability at each node in the dc power system. It based on perturbing the system at a certain node by injecting a small ac current at this node, and accordingly monitoring the variation of the voltage at this node. Then, the node impedance can be calculated. This node impedance implies the stability status of the system at that node. The concept of the node impedance stability criterion is introduced, and the application of this criterion to a dc power system is investigated, as well.