Abstract: One circuit includes first and second primary terminals for connection to first and second power transmission lines and a current transmission path extending between the primary terminals and having current transmission path portions separated by a third primary terminal. A first current transmission path portion includes at least one primary switching element connected in series between the first and third primary terminals, the second current transmission path portion includes an energy conversion block connected between the second and third primary terminals, and the energy conversion block includes at least one primary energy conversion element for removing energy from the power transmission lines. The control circuit further includes a converter limb connected across the second and third primary terminals that includes an auxiliary converter. The control circuit further includes a control unit which controls the auxiliary converter to selectively provide a voltage source.

Abstract: A voltage source converter (30) comprises a converter limb (36), having primary and secondary limbs connected in parallel between first and second DC terminals (32,34), the primary limb element including first and second primary limb element portions (38,40) separated by a third terminal (42), being connectable to an AC electrical network (46), each primary limb element portion (38,40) including at least one primary switching element (50), the secondary limb including first and second secondary limb element portions (52,54) separated by a junction (56), and including a DC side chain-link converter (58), and a connection interconnecting the third terminal (42) and the junction (56) wherein the voltage source converter (30) further includes a control unit (62) controlling the switching of the respective switching elements.

Abstract: A voltage source converter includes a converter limb having limb portions separated by an AC terminal and extending between DC terminals, each limb portion including a primary switching element to switch the limb portion into and out of circuit. The converter further includes an auxiliary limb. The primary switching element of each limb portion is switchable to switch the auxiliary limb into and out of circuit with the corresponding limb portion. The converter further includes a control unit to, in one mode, inject a circulation current that flows in one direction in one of the limb portions and minimize a current flowing in the opposite direction in that limb portion. Each primary switching element switches the respective limb portion into or out of circuit following the minimization of the limb portion current by the circulation current.

Abstract: A voltage source converter includes three branches connected at a first end to a junction to form a star configuration, the second end of each branch defining a DC terminal, the second ends of the second and third branches being connectable to a first DC voltage, and the second ends of the first and second branches being connectable to a second DC voltage. The first and second branches include primary switching elements, and the third branch includes a primary inductive element. The converter includes a converter limb connected in parallel with one of the first and second branches, the converter limb including a chain-link auxiliary converter including multiple series-connected modules controllable to selectively provide a voltage source to modify a branch voltage across the branch connected in parallel with the converter limb, each module including at least one secondary switching element and at least one energy storage device.

Abstract: A control circuit comprising: first and second terminals for respective connection to first and second power transmission lines; a current transmission path extending between the first and second terminals and having first and second current transmission path portions separated by a third terminal, either or both of the first and second current transmission path portions including at least one module, the or each module including at least one energy storage device; an auxiliary terminal for connection to ground or the second power transmission line; an energy conversion block for removing energy from the power transmission lines, the energy conversion block extending between the third and auxiliary terminals such that the energy conversion block branches from the current transmission path, the energy conversion block including at least one energy conversion element; and a control unit which selectively removes the or each energy storage device from the current transmission path.

Abstract: A voltage source converter includes a converter limb having limb portions separated by an AC terminal and extending between DC terminals, each limb portion including a primary switching element to switch the limb portion into and out of circuit. The converter further includes an auxiliary limb. The primary switching element of each limb portion is switchable to switch the auxiliary limb into and out of circuit with the corresponding limb portion. The converter further includes a control unit to, in one mode, inject a circulation current that flows in one direction in one of the limb portions and minimize a current flowing in the opposite direction in that limb portion. Each primary switching element switches the respective limb portion into or out of circuit following the minimization of the limb portion current by the circulation current.

Abstract: The present disclosure relates to control circuits. One circuit includes first and second primary terminals for connection to first and second power transmission lines and a current transmission path extending between the primary terminals and having current transmission path portions separated by a third primary terminal. A first current transmission path portion includes at least one primary switching element connected in series between the first and third primary terminals, the second current transmission path portion includes an energy conversion block connected between the second and third primary terminals, and the energy conversion block includes at least one primary energy conversion element for removing energy from the power transmission lines. The control circuit further includes a converter limb connected across the second and third primary terminals that includes an auxiliary converter.

Abstract: A voltage source converter comprises: at least two converter limbs, each converter limb extending between DC terminals and having limb portions separated by an AC terminal. Each limb portion includes at least one switching element and at least one chain-link converter including series-connected modules. Each module includes at least one switching element and at least one energy storage device that combine to selectively provide a voltage source. The chain-link converter(s) form a branch to interconnect two AC terminals. Each limb portion is switchable to switch the corresponding chain-link converter(s) into and out of circuit with a respective DC terminal. The chain-link converter(s) is switchable to control the configuration of an AC voltage at each corresponding AC terminal. The converter further includes a control unit that coordinates the switching of the limb portions and the chain-link converter(s) to cause transfer of real power between the AC and DC electrical networks.

Abstract: A voltage source converter (30) comprises a converter limb (36), having primary and secondary limbs connected in parallel between first and second DC terminals (32,34), the primary limb element including first and second primary limb element portions (38,40) separated by a third terminal (42), being connectable to an AC electrical network (46), each primary limb element portion (38,40) including at least one primary switching element (50), the secondary limb including first and second secondary limb element portions (52,54) separated by a junction (56), and including a DC side chain-link converter (58), and a connection interconnecting the third terminal (42) and the junction (56) wherein the voltage source converter (30) further includes a control unit (62) controlling the switching of the respective switching elements.

Abstract: A voltage source converter includes a converter limb extending between DC terminals and having limb portions separated by an AC terminal, the DC terminals being connectable to a DC electrical network and the AC terminal being connectable to an AC electrical network. Each limb portion includes at least one switching element and a chain-link converter including a series-connected modules, each module including at least one switching element and at least one energy storage device combining to selectively provide a voltage source. The chain-link converter is connected to the AC terminal, and the switching element(s) of each limb portion is switchable to switch the chain-link converter into and out of circuit with the corresponding DC terminal. The voltage source includes a control unit which coordinates the switching of the switching elements of the limb portions and the switching element(s) in each module of the chain-link converter.

Abstract: A control circuit (20) comprises: first and second terminals (22,24) for respective connection to first and second power transmission lines (26,28); a current transmission path (30,32) extending between the first and second terminals (22,24), the current transmission path (30,32) including at least one module (36), the or each module (36) including at least one energy storage device, the current transmission path (30,32) including at least one inductor (38); a control unit (46) which selectively removes the or each energy storage device of the or each module from the current transmission path (30,32) to modulate a voltage across the or each inductor (38) in a filtering mode to modify current flowing through the current transmission path (30,32) and thereby filter one or more current components from the power transmission lines (26,28); and at least one energy conversion element, wherein the control unit (46) selectively removes the or each energy storage device of the or each module (36) from the current tran

Abstract: A control circuit (20) comprising: first and second terminals (22,24) for respective connection to first and second power transmission lines (26,28); a current transmission path extending between the first and second terminals (22,24) and having first and second current transmission path portions (30,32) separated by a third terminal (34), either or both of the first and second current transmission path portions (30,32) including at least one module (36), the or each module (36) including at least one energy storage device; an auxiliary terminal (42) for connection to ground or the second power transmission line (28); an energy conversion block for removing energy from the power transmission lines (26,28), the energy conversion block extending between the third and auxiliary terminals (34,42) such that the energy conversion block branches from the current transmission path, the energy conversion block including at least one energy conversion element (44); and a control unit (46) which selectively removes the