Abstract: The control circuit includes first and second primary terminals for connection to a DC network, a secondary terminal connected in series between the first and second primary terminals and at least one auxiliary energy conversion element and an auxiliary terminal. The first and second primary terminals have a plurality of modules and a plurality of primary energy conversion elements connected in series therebetween to define a current transmission path, each module including at least one energy storage device, each energy storage device being selectively removable from the current transmission path.

Abstract: A DC to DC converter assembly, for connecting first and second high voltage DC power transmission networks, comprising first and second modular multilevel converters, each converter including a first converter limb having first and second limb portions, each limb portion including a least one module switchable to selectively provide a voltage source and thereby vary the magnitude ratio of a DC voltage (V1, V2) across the first and second terminals of a respective converter and an AC voltage (VAC) at the third terminal of the corresponding converter, the DC to DC converter assembly further including a first link electrically connecting the third terminal of one converter, with the third terminal of the other converter, and at least one converter further including a controller configured to switch the first and second limb portions in the first converter limb of the said converter into simultaneous conduction to divert a portion (IDiV1) of current flowing within the said converter away from the first link.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.

Abstract: 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.

Abstract: A power electronic converter (30), for connecting AC and DC networks (46,44) and transferring power therebetween, comprises: first and second DC terminals (32,34) defining a DC link for connection to a DC network (44); wherein, in use, the DC link has a reversible DC link voltage applied thereacross; at least one converter limb (36) extending between the first and second DC terminals (32,34) and having first and second limb portions (38,40) separated by an AC terminal (42) for connection to an AC network (46), each limb portion (38,40) including at least one rationalized module (52) having first and second sets of series-connected current flow control elements (54) connected in parallel with at least one energy storage device (56), each set of current flow control elements (54) including a primary active switching element to selectively direct current through the energy storage device (56) and a primary passive current check element to limit current flow through the rationalized module (52) to a single direct

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: There is a control circuit comprising first and second DC terminals for connection to a DC network, the first and second DC terminals having a plurality of modules and at least one energy conversion element connected in series therebetween to define a current transmission path, the plurality of modules defining a chain-link converter, each module including at least one energy storage device, the or each energy storage device being selectively removable from the current transmission path to cause a current waveform to flow from the DC network through the current transmission path and the or each energy conversion element and thereby remove energy from the DC network, the or each energy storage device being selectively removable from the current transmission path to modulate the current waveform to maintain a zero net change in energy level of the chain-link converter.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.

Abstract: A power electronic converter (30), for connecting AC and DC networks (46,44) and transferring power therebetween, comprises: first and second DC terminals (32,34) defining a DC link for connection to a DC network (44); wherein, in use, the DC link has a reversible DC link voltage applied thereacross; at least one converter limb (36) extending between the first and second DC terminals (32,34) and having first and second limb portions (38,40) separated by an AC terminal (42) for connection to an AC network (46), each limb portion (38,40) including at least one rationalised module (52) having first and second sets of series-connected current flow control elements (54) connected in parallel with at least one energy storage device (56), each set of current flow control elements (54) including a primary active switching element to selectively direct current through the energy storage device (56) and a primary passive current check element to limit current flow through the rationalised module (52) to a single direct

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

Abstract: There is a control circuit comprising first and second DC terminals for connection to a DC network, the first and second DC terminals having a plurality of modules and at least one energy conversion element connected in series therebetween to define a current transmission path, the plurality of modules defining a chain-link converter, each module including at least one energy storage device, the or each energy storage device being selectively removable from the current transmission path to cause a current waveform to flow from the DC network through the current transmission path and the or each energy conversion element and thereby remove energy from the DC network, the or each energy storage device being selectively removable from the current transmission path to modulate the current waveform to maintain a zero net change in energy level of the chain-link converter.

Abstract: The control circuit includes first and second primary terminals for connection to a DC network, a secondary terminal connected in series between the first and second primary terminals and at least one auxiliary energy conversion element and an auxiliary terminal. The first and second primary terminals have a plurality of modules and a plurality of primary energy conversion elements connected in series therebetween to define a current transmission path, each module including at least one energy storage device, each energy storage device being selectively removable from the current transmission path.

Abstract: A power electronic converter (30)is for use in high voltage direct current power transmission and reactive power compensation, the power electronic converter (30) including three phase elements (32) defining a star connection (36) and a converter unit (34) including first and second DC terminals (50,52) for connection in use to a DC network (56) and three AC terminals (54), the converter unit (34) including a plurality of switching elements (70,74) controllable in use to facilitate power conversion between the AC and DC networks (44,56), the power electronic converter (30) further including a third DC terminal (78) connected between the first and second DC terminals (50,52), the third DC terminal (78) being connected to a common junction (40) of the star connection (36) to define an auxiliary connection (82), the auxiliary connection (82) including at least one dump resistor (84) connected between the common junction (40) and the third DC terminal (78), wherein the switching elements (70,74) of the converter

Abstract: A DC to DC converter assembly, for connecting first and second high voltage DC power transmission networks, comprising first and second modular multilevel converters, each converter including a first converter limb having first and second limb portions, each limb portion including a least one module switchable to selectively provide a voltage source and thereby vary the magnitude ratio of a DC voltage (V1, V2) across the first and second terminals of a respective converter and an AC voltage (VAC) at the third terminal of the corresponding converter, the DC to DC converter assembly further including a first link electrically connecting the third terminal of one converter, with the third terminal of the other converter, and at least one converter further including a controller configured to switch the first and second limb portions in the first converter limb of the said converter into simultaneous conduction to divert a portion (IDiV1) of current flowing within the said converter away from the first link.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation includes at least one converter limb, which includes first and second DC terminals and an AC terminal. Each converter limb defines first and second limb portions connected in series between the AC terminal and a respective one of the first and second DC terminals. Each limb portion includes a chain-link converter connected in series with at least one primary switching element. Each chain-link converter includes a plurality of modules connected in series, and each module includes at least one secondary switching element connected to at least one energy storage device. Each primary switching element in each limb portion of a respective converter limb selectively defines a circulation path which carries a DC circulation current to regulate the energy level of at least one energy storage device in a respective chain-link converter.

Abstract: In the field of high voltage DC power transmission there is a need for a small, lightweight, inexpensive, and reliable means of connecting first and second high voltage DC power transmission networks. A DC to DC converter assembly, for connecting first and second high voltage DC power transmission networks, comprises an inverter which has first and second terminals which are connectable in use to a first high voltage DC power transmission network. The inverter is defined by a modular multilevel converter which includes a first inverter limb that extends between the first and second terminals and has first and second inverter limb portions that are separated by a third terminal. Each inverter limb portion includes at least one rationalised module which has first and second sets of series-connected current flow control elements that are connected in parallel with at least one energy storage device.

Abstract: A power electronic converter (30)is for use in high voltage direct current power transmission and reactive power compensation, the power electronic converter (30) including three phase elements (32) defining a star connection (36) and a converter unit (34) including first and second DC terminals (50,52) for connection in use to a DC network (56) and three AC terminals (54), the converter unit (34) including a plurality of switching elements (70,74) controllable in use to facilitate power conversion between the AC and DC networks (44,56), the power electronic converter (30) further including a third DC terminal (78) connected between the first and second DC terminals (50,52), the third DC terminal (78) being connected to a common junction (40) of the star connection (36) to define an auxiliary connection (82), the auxiliary connection (82) including at least one dump resistor (84) connected between the common junction (40) and the third DC terminal (78), wherein the switching elements (70,74) of the converter

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation includes at least one converter limb, which includes first and second DC terminals and an AC terminal. Each converter limb defines first and second limb portions connected in series between the AC terminal and a respective one of the first and second DC terminals. Each limb portion includes a chain-link converter connected in series with at least one primary switching element. Each chain-link converter includes a plurality of modules connected in series, and each module includes at least one secondary switching element connected to at least one energy storage device. Each primary switching element in each limb portion of a respective converter limb selectively defines a circulation path which carries a DC circulation current to regulate the energy level of at least one energy storage device in a respective chain-link converter.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.