DC to DC converter assembly

摘要

A DC-to-DC converter assembly includes an inverter having first and second terminals connectable to a power transmission network. The inverter has a modular multilevel converter including a first inverter limb extending between the first and second terminals with first and second inverter limb portions separated by a third terminal. Each inverter limb portion includes at least one rationalized module having first and second sets of series-connected current flow control elements connected in parallel with an energy storage device. The current flow control elements include an active switching element directing current through the energy storage device and a passive current check element limiting current flow to one direction. The current flow control elements and energy storage device provide a voltage source to synthesize an AC voltage at the third terminal. A rectifier is electrically connected to the third terminal and connectable to a second power transmission network.

主权项

1. A DC to DC converter assembly, for connecting first and second high voltage DC power transmission networks, comprising:
an inverter having first and second terminals connectable in use to a first high voltage DC power transmission network, the inverter being defined by a modular multilevel converter including a first inverter limb extending between the first and second terminals and having first and second inverter limb portions separated by a third terminal, each inverter limb portion including at least one rationalised module having first and second sets of series-connected current flow control elements connected in parallel with at least one energy storage device in a full-bridge arrangement so as to define a 2-quadrant bipolar rationalised module that can provide zero, positive or negative voltage while conducting current in a single direction from the first high voltage DC network to the second high voltage DC network, each set of current flow control elements including an active switching element to selectively direct current through the energy storage device and a passive current check element to limit current flow through the rationalised module to a single direction, the current flow control elements and the or each energy storage device combining to selectively provide a voltage source to synthesise an AC voltage at the third terminal; and a rectifier electrically connected to the third terminal of the inverter by a first direct electrical link and connectable in use to a second high voltage DC power transmission network, the rectifier being configured to convert the AC voltage conveyed by the first direct electrical link into a second DC voltage for supply to the second high voltage DC power transmission network, wherein the DC to DC converter assembly is configured to transfer power from the first high voltage DC power transmission network to the second high voltage DC power transmission network, the first high voltage DC power transmission network having a different voltage than the second high voltage DC power transmission network.