Patent ID: 6898095
Filing Date: 2005-05-24
Classification: H02M

Abstract:
1. A VSC-converter for converting direct voltage into alternating voltage and vice versa, which comprises a series connection of at least two current valves arranged between two poles, a positive and a negative, of a direct voltage side of the converter, each current valve consisting of several series connected circuits, each of which circuits comprising a semiconductor component of turn-off type and a rectifying component connected in antiparallel therewith, an alternating voltage phase line being connected to a midpoint, denominated phase output, of the series connection of current valves between two of said current valves while dividing the series connection into two equal parts, wherein each of the series connected circuits of the respective current valve, in order to make possible a good voltage distribution between the semiconductor components of turn-off type included in the respective current valve, comprises a snubber capacitor connected in parallel with the semiconductor component of turn-off type included in the circuit, and that the converter comprises a resonance circuit for recharging the snubber capacitors of the current valves so as to thereby make possible a turn-on of the semiconductor components of turn-off type of the current valves at low voltage across the semiconductor components.