Optimizing DC power distribution network stability using root locus analysis

The stability of DC power distribution networks are very much affected by the interaction between the negative dynamic input resistances of DC/DC or DC/AC power converters and reactive elements (e.g. EMI-filters, parasitic inductances, .,.) present in the network. The more "old-fashioned" centralized power supplies with bulky and damping electrolytic capacitors are replaced by modern distributed solutions with low-ohmic filter elements (e.g. ceramic capacitors) the more severe the stability issue becomes. The modular architecture of telecommunications systems means that a huge number of more or less different DC power distribution networks are possible. A clear and simple strategy is therefore necessary in order to keep all these network implementations safe in terms of stability. Our paper gives an insight into the strategy we use to ensure DC power distribution network stability under all conditions. This strategy is to a great extent based on a root locus / eigenvalue analysis performed at different levels.