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Asea Brown Boveri Ab

Ingemar Blidberg

Bo Bijlenga

Björn Jacobson

Olle Ekwall

Roland Siljeström

Kjell Svensson

Bj&ouml;rn Jacobson

Henrik Spjuth

In a method for control of a converter for conversion of dc voltage into ac voltage or dc voltage and vice versa, in which an output of the converter may alternatively be connected to a positive pole, a negative pole or a center of a dc voltage side of the converter in the form of different so-called main states, there is carried out, when changing between main states via a so-called minor commutation loop, an extra sequence in the form of a delayed turn-on of semiconductor elements in one unit of the converter relative to semiconductor elements in another unit in a pair of units of the converter.

Converter and a method for controlling a converter

In a VSC-converter for converting direct voltage to alternating voltage and conversely at least one phase leg (,) is arranged according to a NPC-connection. At least two of the four current valves (,) and the clamping rectifying members (,) thereof are arranged close to each other and so that commutation currents generated on commutation of the converter therein will flow in substantially opposite directions.

VSC-converter

A VSC converter has each current valve of a phase leg formed by a plurality of units of semiconductor elements and rectifying members, located on top of each other forming at least one stack. The phase leg is constructed according to the flat cable principle with the phase leg formed by such stacks arranged side by side in pairs at small distances (d) running back and forth. A cooling plate of electrically conducting material is arranged between each unit in the stacks.

Voltage converter having a commutation circuit with reduced inductance

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Ludvika, Sweden

Ingemar Blidberg