| 摘要 |
A high-voltage direct current voltage source converter (HVDC-VSC) 10 comprises at least one converter limb 12 that includes first and second DC terminals 14, 16 for connection to a DC network 18. Each converter limb 12 includes first and second limb portions 20A, 20B separated by an AC terminal 22 for connection to an AC network 24. Each limb portion 20A, 20B includes a primary switching element 26A, 26B connected in series with a chain-link converter 28A, 28B that provides a stepped variable voltage. The voltage source converter 10 also includes a control unit 36 programmed to switch the primary switching element 26A, 26B in each of the first and second limb portions 20A, 20B between conducting and non-conducting configurations to selectively switch the corresponding chain-link converter 28A, 28B in, and out of, circuit. In its non-conducting configuration, each primary switching element 26A, 26B transitions between a non-voltage supporting state and a voltage supporting state. While switched out of circuit, each chain-link converter 28A, 28B is operated to generate a varying voltage waveform to reduce the voltage range that the corresponding primary switching element 26A, 26B is exposed to while in its voltage supporting state. |
