Modeling of multiport DC busses in power-electronic systems

This paper deals with dynamic modeling of multi-port DC busses, which are increasingly applied in various DC-power distribution systems, such as hybrid powertrains and DC microgrids. Parasitic impedances of long DC cabling together with distributed DC capacitors introduce a potential risk of small-signal instabilities in the DC bus, if resonance frequencies of the bus appear below (or around) switching frequencies of power-electronic converters. In order to predict the resonance behavior of the bus, a systematic approach for dynamic modeling of the DC bus in power-electronic systems is presented. The DC-bus model is validated by means of experiments. Furthermore, application of the model in small-signal analysis and time-domain simulations is illustrated.