Control of extinction angle for a line-commutated converter
AssigneeABB Group Services Center AB
InventorIngvar Hagman
Life of this patent
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Abstract
A method for control of an extinction angle of a line-commutated converter in dependence on a minimum reference value for the extinction angle. The converter has a plurality of valves, each one of the plurality of valves having at least one semiconductor element capable of being fired, and the device has a unit for generating firing control pulses for a commutating valve in dependence on the minimum reference value of the extinction angle according to a given criterion for commutation of a direct current through the converter. The device has a unit for continuously forming an operating value of recovery time for the semiconductor element of a decommutating valve, and a unit for forming the minimum reference value of the extinction angle in dependence of the operating value.
Claims10
A method for control of an extinction angle of a line-commutated converter in dependence on a minimum reference value for the extinction angle, the converter having a plurality of valves, each one of the plurality of valves having at least one semiconductor element capable of being fired, whereby, for a commutating valve, firing control pulses are generated in dependence on the minimum reference value of the extinction angle according to a given criterion for commutation of a direct current through the converter, wherein an operating value of recovery time (tq) for the semiconductor elements of a decommutating valve is continuously formed, and wherein the minimum reference value of the extinction angle is formed in dependence on said operating value.
A device for control of an extinction angle of a line-commutated converter in dependence on a minimum reference value for the extinction angle, the converter having a plurality of valves, each one of the plurality of valves having at least one semiconductor element capable of being fired, the device comprising:
- means for generating firing control pulses for a commutating valve in dependence on the minimum reference value for the extinction angle according to a given criterion for commutation of a direct current through the converter;
- means for continuously forming an operating value of recovery time (tq) for the semiconductor element of a decommutating valve;
- and
- means for forming the minimum reference value for the extinction angle in dependence on said operating value.
Dependencies are inferred from the claim text.