{Bidirectional, high-power DC transformer}

Title{Bidirectional, high-power DC transformer}
Publication TypeJournal Article
Year of Publication2009
AuthorsJovcic D
JournalIEEE Transactions on Power Delivery
KeywordsDC-DC power conversion, High-voltage dc transmission, Thyristor converters
AbstractThis paper studies a bidirectional dc?dc converter concept which is$\backslash$ncapable of achieving very high stepping ratios with MW level power$\backslash$ntransfers. The converter can find potential application in connecting$\backslash$nhigh-power dc sources, interfacing to high-voltage dc transmission$\backslash$nor to flexible ac transmission system elements. The converter is$\backslash$nbased on two resonant circuits which share a common ac capacitor.$\backslash$nThe topology is simple and utilizes thyristors with potentially all$\backslash$nsoft switchings. Complete analytical modelling is presented which$\backslash$nenables systematic design procedure for the converter. The detailed$\backslash$ndigital simulation on PSCAD platform confirms satisfactory operation$\backslash$non a 5-MW test system, which connects 4-kV dc source to an 80-kV$\backslash$nhigh voltage dc grid. The converter shows good responses to rapid$\backslash$nchanges in power magnitude/direction and it is concluded that robustness$\backslash$nto terminal voltage disturbances is excellent. Since the highest-power$\backslash$nphase-control thyristors are employed, the converter can potentially$\backslash$nbe used at much higher power levels. The passive components are of$\backslash$nreasonable size.