Bidirectional, high-power DC transformer

TitleBidirectional, 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\ncapable of achieving very high stepping ratios with MW level power\ntransfers. The converter can find potential application in connecting\nhigh-power dc sources, interfacing to high-voltage dc transmission\nor to flexible ac transmission system elements. The converter is\nbased on two resonant circuits which share a common ac capacitor.\nThe topology is simple and utilizes thyristors with potentially all\nsoft switchings. Complete analytical modelling is presented which\nenables systematic design procedure for the converter. The detailed\ndigital simulation on PSCAD platform confirms satisfactory operation\non a 5-MW test system, which connects 4-kV dc source to an 80-kV\nhigh voltage dc grid. The converter shows good responses to rapid\nchanges in power magnitude/direction and it is concluded that robustness\nto terminal voltage disturbances is excellent. Since the highest-power\nphase-control thyristors are employed, the converter can potentially\nbe used at much higher power levels. The passive components are of\nreasonable size.