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 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 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:
Power converters are disclosed. One power electronic converter for connecting AC and DC electrical networks and transferring power therebetween includes a converter limb extending between two DC terminals and having limb portions separated by an AC terminal. Each limb portion includes a chain-link converter including at least one rationalized module that has first and second sets of series-connected current flow control elements connected in parallel with at least one energy storage device. The current flow control elements and energy storage device(s) in each rationalized module combine to selectively provide a voltage source to control the configuration of an AC voltage at the AC terminal. The converter further includes a controller to selectively control the switching of the current flow control elements to simultaneously switch both limb portions into circuit to form a current circulation path including the converter limb and the DC electrical network.
Abstract:
An alternate arm converter includes at least one converter limb that defines first and second limb portions. Each limb portion includes at least one director switch connected in series with a chain-link converter between one of two DC terminals and an AC terminal of the converter. The chain-link converters are operable to generate a voltage waveform at the AC terminal, and the director switches are operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal. The converter also includes a controller configured to selectively control the switching of each director switch to form a current circulation path including each limb portion and the DC network. The controller, during formation of the current circulation path, forces an alternating current to flow through the current circulation path to transfer energy between the chain-link converters of the limb portions.
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 (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 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 direction, the current flow control elements (54) and the or each energy storage device (56) combining to selectively provide a voltage source to synthesise an AC voltage at the AC terminal (42); and a first controller (60) to selectively switch the or each rationalised module (52) in each limb portion (38,40) to control the configuration of the AC voltage at the corresponding AC terminal (42) so as to transfer power from the AC network (46) to the DC network (44) in an AC to DC power transfer mode and to transfer power from the DC network (44) to the AC network (46) in a DC to AC power transfer mode, wherein each limb portion (38,40) includes: one or more secondary passive current check elements (48) to limit current flow through the corresponding limb portion (38,40) to a single direction between the corresponding AC and DC terminals (42,32,34), the or each secondary passive current check element (48) being connected in series with the or each rationalised module (52); or one or more secondary active switching elements that is connected in series with the or each rationalised module (52).
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.