Analysis of small-signal voltage stability for a reduced-order cascade-connected MVDC power system

Voltage stability is a fundamental issue to be addressed in the future All-Electric Ships (AESs) based on DC distribution. Focusing on a cascade-connected MVDC power system (i.e. a feeder DC-DC converter supplying a load DC-DC converter), the small-signal analysis is the first study to be accomplished for investigating the effect of load converter's control bandwidth on the system stability. Albeit such an evaluation may be performed on the complete fifth order model by determining the Routh-Hurwitz coefficients, a convenient model reduction can simplify this study. In such a way, it is possible to provide an analytical and simple formula for defining the minimum acceptable time constant (i.e. the maximum load converter control bandwidth). Once identified such a minimum time constant, some simulations show how the complete and reduced models work in presence of three different filter arrangements on the load converter side.