Patent US2157729A successfully refreshed from Google Patents.
US5155673A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thyristor converter protection method and apparatus
Assignee: Toshiba Corp
•
Filing: 1991-05-09
•
Granted: 1992-10-13
•
Expires: 2011-05-09
Abstract
Abstract A method and apparatus for protecting thyristors in a power converter from overvoltages. Voltage detectors determine if the forward voltage of each thyristor has increased in the converter. If such an overvoltage occurs during a predetermined period after the conduction of the thyristor, forced triggering of all the thyristors prevent damage to the thyristors.
Inventors
- 👤 Tadashi Takahashi
- 👤 Katsuro Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:54
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/08; H02M1/088; H02M1/092; H03; H03K; H03K17/00; H03K17/08; H03K17/082; H03K17/0824; Y; Y10; Y10S; Y10S323/00; Y10S323/902
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
83 words
A method of protecting a thyristor in a thyristor valve from damage, comprising the steps of: detecting a forward voltage of the thyristor; determining if the forward voltage equals a predetermined voltage; determining a set time period following the conduction period of the thyristor, said set time period starting at a time when the circuit voltage becomes zero from a reverse voltage; and generating a forced supply of triggering signals when the detected voltage equals said predetermined voltage during the set time period.
Claim 2
Independent Claim
83 words
A method of protecting a thyristor in a thyristor valve from damage, comprising the steps of: detecting a forward voltage of the thyristor; determining if the forward voltage equals a predetermined voltage; determining a set time period following the conduction period of the thyristor, said set time period starting at a time when the circuit voltage becomes zero from a reverse voltage; and generating a forced supply of triggering signals when the detected voltage equals said predetermined voltage during the set time period.
Claim 3
Dependent Claim
23 words
A method according to claim 1, wherein said triggering signals are generated if the forward voltage becomes zero during said set time period.
Claim 4
Dependent Claim
41 words
A method according to claim 1, wherein said thyristor is connected to a plurality of similar thyristors and where said triggering signals are generated if the forward voltage imposed on the thyristors in said set time period equals a set value.
Claim 5
Dependent Claim
15 words
A method according to claim 1, wherein said set time period includes a margin angle.
Claim 6
Dependent Claim
17 words
A method according to claim 1, wherein said predetermined voltage is set to a limit self-triggering voltage.
Claim 7
Independent Claim
99 words
An apparatus for protecting a thyristor in a thyristor valve comprising: a forward voltage detecting means for detecting the forward voltage of said thyristor; an overvoltage detecting means for determining if said forward voltage of said thyristor equals a predetermined voltage; a period setting means for determining a set time period following the conduction period of said thyristor, said set time period starting at a time when the circuit voltage becomes zero from a reverse voltage; and means for generating a forced supply of triggering signals when the detected voltage equals said predetermined voltage during the set time period.
Claim 8
Independent Claim
99 words
An apparatus for protecting a thyristor in a thyristor valve comprising: a forward voltage detecting means for detecting the forward voltage of said thyristor; an overvoltage detecting means for determining if said forward voltage of said thyristor equals a predetermined voltage; a period setting means for determining a set time period following the conduction period of said thyristor, said set time period starting at a time when the circuit voltage becomes zero from a reverse voltage; and means for generating a forced supply of triggering signals when the detected voltage equals said predetermined voltage during the set time period.
Claim 9
Dependent Claim
30 words
An apparatus according to claim 6, wherein said thyristor is connected in series with a plurality of similar thyristors each of said thyristors having a corresponding forward voltage detecting means.
Claim 10
Dependent Claim
14 words
An apparatus according to claim 6, wherein said set period includes a margin angle.
Claim 11
Dependent Claim
17 words
An apparatus according to claim 6, wherein said predetermined voltage is set to a limit self-triggering voltage.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-13 | 1996-04-13 | 1996-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-13 | 2000-04-13 | 2000-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-13 | 2004-04-13 | 2004-10-13 | $7700.00 | Window Closed / Lapsed |