| 摘要 |
A voltage source converter (30) comprises a converter limb (36), the converter limb (36) extending between first and second DC terminals (32,34) and having primary and secondary limb elements connected in parallel between the first and second DC terminals (32,34), each DC terminal (32,34) being connectable to a DC electrical network (44), the primary limb element including first and second primary limb element portions (38,40) separated by a third terminal (42), the 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), each primary switching element (50) being switchable to switch the corresponding primary limb element portion (38,40) into and out of circuit between a respective one of the DC terminals (32,34) and the third terminal (42), the secondary limb element including first and second secondary limb element portions (52,54) separated by a junction (56), each secondary limb element portion (52,54) including a DC side chain-link converter (58), each chain-link converter (58) including a plurality of series-connected modules (60), each module (60) of each chain-link converter (58) including at least one secondary switching element and at least one energy storage device, the or each secondary switching element and the or each energy storage device in each module (60) combining to selectively provide a voltage source, the converter limb (36) further including a connection interconnecting the third terminal (42) and the junction (56) to form a star configuration in which a first branch of the star configuration includes the connection, a second branch of the star configuration includes the first secondary limb element portion (52), a third branch of the star configuration includes the second secondary limb element portion (54) and the junction (56) defines a mid-point of the star configuration, wherein the voltage source converter (30) further includes a control unit (62) which controls the switching of each primary switching element to switch the corresponding primary limb element portion (38,40) into and out of circuit between the corresponding DC terminal (32,34) and the third terminal (42) to selectively transfer power between the AC and DC electrical networks (46,44) via each of the primary limb element portions (38,40), the control unit (62) further controlling the switching of the or each secondary switching element in each module (60) of each DC side chain-link converter (58) to control the configuration of an AC voltage waveform at the third terminal (42). |
