Method for producing rectifier with switches of asymmetric voltage breakdown strengths
AssigneeBBC Brown, Boveri & Company, Limited
InventorsPeter Etter, Werner Faust
Life of this patent
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Abstract
A rectifier for a medium voltage rectifier system as well as for high voltage-direct current transmission includes a plurality of thyristor switches. The switches have asymmetric voltage breakdown strengths, the asymmetry being at least 10% for the forward blocking direction compared with the reverse blocking direction. The thyristor switches are dimensioned voltage-wise to safely block even long lasting overvoltages in both the forward and reverse blocking directions occurring during operation and to withstand momentary surge and switching voltages limited by an overvoltage suppressor in the reverse blocking direction.
Claims7
A method for producing rectifiers for medium and high voltage systems at reduced cost comprising the steps of:
- providing a rectifier element including a plurality of series connected thyristor switches,
- constructing said rectifier element so as to have an asymmetric breakdown voltage characteristic in which the breakdown strength is at least 10% greater in the reverse direction than in the forward direction;
- and,
- dimensioning said rectifier element voltagewise to safely block even long lasting overvoltages in both the forward and reverse blocking directions occurring during operation and to withstand momentary surge and switching voltages limited by an overvoltage suppressor in the reverse blocking direction.
Dependencies are inferred from the claim text.