Experimental verification of limiting fault currents in MVDC systems by using modular multilevel converters

Medium voltage direct current (MVDC) system poses an attractive technology for the development of high power all electric ships in the future. The Modular Multilevel Converter (MMC) is a potential candidate to be used as an AC/DC interface in fault current limited MVDC systems. A Controller Hardware in the Loop (CHIL) setup and the experimental setup have been designed for the initial verification of the fault current limiting function of MMC converters. A novel MMC averaged value model (AVM) is proposed in this paper for the purpose of emulating the DC side dynamics. The experimental results show that the MMC is able to limit the fault current under the investigated scenarios of load steps and arc faults causing an over current. However, the AVM requires additional features which are to be implemented in future works to better reproduce the observed behavior.