Protective device for at least one thyristor
AssigneeSiemens Aktiengesellschaft
InventorGerd Thiele
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Abstract
This invention concerns a protective device for at least one thyristor. Separate measuring sensors are provided for determining the thyristor parameters of current and the magnitude and rising slope of the thyristor voltage. The measuring sensors are followed by a comparison stage which compares the parameters with definite, predetermined conditions, and transmits a trigger pulse for the thyristor. With the protective device according to the invention, the thyristor can be fired by means of its control electrode during the recovery time of the thyristor, if an overvoltage occurs.
Claims12
Apparatus for protecting a thyristor during its recovery time comprising:
- means for generating a signal proportional to the thyristor current,
- means for generating a slope signal proportional to the arising slope of the thyristor voltage,
- means for generating a signal proportional to the magnitude of the thyristor voltage,
- means for generating comparison signals if said current signal, slope signal, and voltage signal are each different from predetermined values, and
- means responsive to said comparison signals for generating a firing pulse for the thyristor.
Dependencies are inferred from the claim text.