Power converter
AssigneeKabushiki Kaisha Toshiba
InventorSumio Kobayashi
Life of this patent
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Abstract
A power converter comprises a pulse generator capable of outputting two different levels of gate power. A thyristor (LTT) is turned on by the first gate power output from the pulse generator, and the second gate power is supplied to the thyristor (LTT) during the transient period from the time the thyristor valve current is cut off to the time the withstand voltage of the thyristor (LTT) recovers to the rated value. The second gate power is set at a low level by which the thyristor (LTT) will not be turned on when the second gate power with the normal level of voltage is applied to the thyristor.
Claims15
A power converter having a thyristor valve which is turned on by being supplied with a gate power to flow a current in one direction, comprising:
- trigger pulse generating means for generating a trigger pulse signal to supply to the thyristor valve a first gate power to turn on the thyristor valve;
- detecting means for detecting, during a turn a transient period from a time at which the thyristor valve current is cut off to a time at which a withstand voltage of the thyristor valve recovers to a rated value;
- and
- supplemental pulse generating means for continuously generating a supplemental pulse signal to supply a second gate power to the thyristor valve during the transient period detected by said detecting means, the second gate power being set at a level lower than that of the first gate power so that the thyristor valve is not turned on.
A power converter having a thyristor valve which is turned on by being supplied with a gate power to flow a current in one direction, comprising:
- trigger pulse generating means for generating a trigger pulse signal to supply to the thyristor valve a first gate power to turn on the thyristor valve;
- and
- supplemental pulse generating means for continuously generating a supplemental pulse signal to supply a second gate power lower than the first gate power to the thyristor valve during a predetermined period from a time when the current is cut off,
- wherein the thyristor valve comprises:
- at least one light-triggered thyristor which is supplied with a light-triggered signal as the trigger pulse signal,
- wherein the trigger pulse generating means includes:
- a power source;
- a light emitting element connected to the power source;
- and
- a first switching element arranged between the power source and the light emitting element, and which is turned on when the first gate power is supplied to the at least one light-triggered thyristor, thereby making the light emitting element output the trigger pulse signal, and
- wherein the supplemental pulse generating means includes:
- a second switching element connected in parallel with the first switching element, and which is turned on when the second gate power is supplied to the at least one light-triggered thyristor, thereby making the light emitting element output a light pulse signal corresponding to the supplemental pulse;
- and
- an impedance connected serially to the second switching element, for setting a current which is supplied to the light emitting element when the second switching element is turned on at a lower level than that of a current supplied to the light emitting element when the first switching element is turned on.
A power converter having a thyristor valve which is turned on by being supplied with a gate power to flow a current in one direction, comprising:
- trigger pulse generating means for generating a trigger pulse signal to supply to the thyristor valve a first gate power to turn on the thyristor valve;
- means for detecting a transient period from a time at which the thyristor valve current is cut off to a time at which a withstand voltage of the thyristor valve recovers to a rated value;
- and
- supplemental pulse generating means for continuously generating a supplemental pulse signal to supply a second gate power to the thyristor valve during the transient period, the second gate power being set at a level such that the thyristor valve is not turned on, and that a predetermined amount of carriers are present in a gate portion of the thyristor valve during the transient period.
A power converter having a thyristor valve, comprising:
- a detecting mechanism configured to detect a transient period from a time at which the thyristor valve current is cut off to a time at which a withstand voltage of the thyristor valve recovers to a rated value;
- and
- a pulse generator which generates a first trigger pulse signal to supply to the thyristor valve a first gate power to turn on the thyristor valve, and which continuously, during the transient period detected by said detecting mechanism, generates a second pulse signal to supply a second gate power to the thyristor valve, the second gate power being set at a level lower than that of the first gate power so that the thyristor valve is not turned on.
Dependencies are inferred from the claim text.