A novel HVDC-link based on hybrid voltage-source converters

In this paper, a novel topology of the HVDC converter is proposed for offshore wind farm applications. A combined structure of a voltage-source converter (VSC) and a 12-pulse diode rectifier is applied to the sending-end station on the offshore side and a hybrid topology of a VSC and 12-pulse SCR converters is employed for a receiving station. The VSC is used not only to control the high DC-link voltage, but also to compensate for the reactive power of the SCR converter without requiring the capacitor banks. In addition, the current harmonics due to the SCR converter can be mitigated, by which the AC filters are not required for the SCR converter. The potential benefits of this hybrid topology include low power losses, low costs, and smaller footprint resulting from using the diode and SCR. The simulation results for 500-MW HVDC transmission system are shown to verify the effectiveness of the proposed method.