| 摘要 |
There is provided a DC to DC converter assembly (20) for interconnecting DC electrical networks (32, 34). The DC to DC converter assembly (20) comprises: first and second converters (22, 24), each converter (22, 24) including first and second DC terminals (26, 28) for connection to a respective one of the DC electrical networks (32, 34), each converter (22, 24) including a converter limb (30) extending between the corresponding first and second DC terminals (26, 28), the converter limb (30) of the first converter (22) having a pair of first limb portions (36a, 36b) separated by a first AC terminal (40), the converter limb (30) of the second converter (24) having a pair of second limb portions (38a, 38b) separated by a second AC terminal (42), each limb portion (36a, 36b, 38a, 38b) including at least one switching element, at least one first limb portion (36a, 36b) including at least one first module (46a), at least one second limb portion (38a, 38b) including at least one second module (46b), the or each module (46a, 46b) including at least one switching element and at least one energy storage device, the or each switching element and the or each energy storage device in each module (46a, 46b) combining to selectively provide a voltage source, the or each switching element in each limb portion (36a, 36b, 38a, 38b) being switchable to switch the corresponding limb portion (36a, 36b, 38a, 38b) into or out of circuit between the corresponding AC and DC terminals (26, 28, 40, 42) to control the configuration of an AC voltage (66, 68) at the corresponding AC terminal (26, 28, 40, 42); an AC transmission link (56), the first AC terminal (40) being connected to the second AC terminal (42) via the AC transmission link (56), the first AC terminal (40) being connected at a first end of the AC transmission link (56), the second AC terminal (42) being connected at a second end of the AC transmission link (56); and a controller (65) configured to selectively control switching of the or each switching element in each limb portion (36a, 36b, 38a, 38b) to control the configuration of the AC voltage (66, 68) at the corresponding AC terminal (40, 42) to: form a current circulation path that includes the AC transmission link (56), at least one first limb portion (36a, 36b) and at least one second limb portion (38a, 38b); and inject a circulation current into the current circulation path to transfer energy between at least one first module (46a) and at least one second module (46b) in the circulation path. |
