Closed Access
A modular multi-level DC-DC converter for HVDC grids
De La Parra, Hector Zelaya
- 1Universidad Jaume I
- 2
- 3Universidad de Concepcion
- 4Universitat Politècnica de València
- 5ABB Corporate Research, Vasteras
Journal
IECON Proceedings (Industrial Electronics Conference)
ISSN
1553-572X
Open Access
closed
Start page
3141
End page
3146
A double-T DC-DC modular multilevel converter (DC-DC-MMC) topology for high-voltage dc (HVdc) applications is presented in this paper. The topology is intended to interconnect large power dc grids with different voltage levels or to control the power flow in meshed dc grids. A two level control hierarchy is used to regulate the dc voltage of each cell. At the top level, dc and circulating ac currents are used to control the total energy in every branch. At the bottom level, the balance of the cell capacitor voltages within a branch is carried out by balancing (N-1) capacitor voltage deviations with respect to the average capacitor voltage. Finally, the operation of the converter is validated by means of PSCAD simulations. Results for the operation of the DC-DC-MMC controlling the power flow between two HVdc grids with different voltage levels are presented. The robustness of the converter has also been proven by simulating the disconnection of one pole of the bipolar dc grid.