Preventing instability in DC distribution systems by using power buffering

Negative incremental impedance of regulated converter loads can cause stability problems in distributed DC power systems. Since the load-side converters usually contain energy storage elements, it is possible to avoid instability through transient control of the load-side converter input impedance. In this paper, bus-side stability is used as a control constraint. It is shown that load-side converter control-loop gain can be modified to improve stability characteristics, or even actively controlled to meet given impedance specifications.