Royal IHC is known for building large dredging vessels which collect soil from the seabed. The vessel needs to remain in position, called dynamic positioning, which is done by large thrusters. These are mostly electrically powered thus the total amount of required power can range up to 50 MWs. Royal IHC wants to investigate the possibility of a DC vessel where the synchronous generator’s AC voltage is rectified via a passive rectifier. The question is how stable this is and what influences the voltage stability.

The thesis focuses on building a model of a DC powered propulsion system that allows analysis of voltage stability of the vessel. The model is generalized and consists of two parallel diesel generator sets with a passive rectifier. These generators are connected to a common DC bus with constant power loads which represent the loads of the vessel. The model is built in Matlab Simulink using the specialized power system toolbox and is verified with an RScad simulation. A measurement-based analysis tool is developed utilizing prony analysis. This allows analyzing the results of the simulation model and data from the field. Both cases are tested, the tool allows to get insight into the stability of the vessel.