US4384248A
Expired / Lapsed
US
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Method and apparatus for detecting shortcircuit in arm of GTO inverter
Assignee: Hitachi Ltd
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Filing: 1980-06-17
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Granted: 1983-05-17
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Expires: 2000-06-17
Abstract
Abstract Shortcircuit in an arm including a series connection of GTO's and reactors of an inverter is detected by sensing a voltage across the reactor. In one method, the shortcircuit in the arm is detected when voltages are coincidently applied to a P-line arm reactor and an N-line arm reactor for a predetermined time period. In another method, it is detected when an integrated value of a voltage across at least one of the reactors exceeds a predetermined level.
Inventors
- 👤 Yasuo Matsuda
- 👤 Kazuo Honda
- 👤 Takeo Maeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:01
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/10; H02H7/12; H02H7/122; H02H7/1225; G; G01; G01R; G01R31/00; G01R31/50; G01R31/52
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
96 words
A method for detecting a shortcircuit in an arm of a GTO inverter provided with at least one pair of arms, each arm being composed of a series connection of a single gate turn-off thyristor and a single reactor, said method comprising the steps of: sensing the voltage across each of said reactors of said paired arms; detecting if said sensed voltages across said reactors last coincidentally for longer than a predetermined time period; and determining the shortcircuit in one of said paired arms when said voltages last coincidentally for longer than said predetermined time period.
Claim 2
Independent Claim
96 words
A method for detecting a shortcircuit in an arm of a GTO inverter provided with at least one pair of arms, each arm being composed of a series connection of a single gate turn-off thyristor and a single reactor, said method comprising the steps of: sensing the voltage across each of said reactors of said paired arms; detecting if said sensed voltages across said reactors last coincidentally for longer than a predetermined time period; and determining the shortcircuit in one of said paired arms when said voltages last coincidentally for longer than said predetermined time period.
Claim 3
Dependent Claim
50 words
A method for detecting a shortcircuit in an arm of a GTO inverter according to claim 1, wherein said predetermined time period is selected to be equal to a time period required for a snubber capacitor of the inverter to be charged to one half of the GTO anode voltage.
Claim 4
Independent Claim
118 words
An apparatus for detecting a shortcircuit in an arm of a GTO inverter provided with at least one pair of arms, each arm being composed of a series connection of a single gate turn-off thyristor and a single reactor, said apparatus comprising: (i) first means connected across one of the reactors of said paired arms for sensing a voltage thereacross; (ii) second means connected across the other of said reactors for sensing a voltage thereacross; (iii) third means connected to said first and second means for ANDing the outputs thereof; and (iv) fourth means connected to the output of said third means for detecting if said third means produces an output for longer than a predetermined time period.
Claim 5
Independent Claim
118 words
An apparatus for detecting a shortcircuit in an arm of a GTO inverter provided with at least one pair of arms, each arm being composed of a series connection of a single gate turn-off thyristor and a single reactor, said apparatus comprising: (i) first means connected across one of the reactors of said paired arms for sensing a voltage thereacross; (ii) second means connected across the other of said reactors for sensing a voltage thereacross; (iii) third means connected to said first and second means for ANDing the outputs thereof; and (iv) fourth means connected to the output of said third means for detecting if said third means produces an output for longer than a predetermined time period.
Claim 6
Dependent Claim
53 words
An apparatus for detecting a shortcircuit in an arm of a GTO inverter according to claim 3, wherein said predetermined time period for said fourth means is selected to be equal to a time period for a snubber capacitor of the inverter to be charged to one half of the GTO anode voltage.
Claim 7
Dependent Claim
45 words
An apparatus for detecting a shortcircuit in an arm of a GTO inverter according to claim 3, wherein said fourth means comprises a pulse width discriminator for determining if the pulse width of the output pulse from said third means has a predetermined pulse width.
Claim 8
Dependent Claim
48 words
An apparatus for detecting a shortcircuit in an arm of a GTO inverter according to claim 5 wherein said pulse width is selected to be equal to the time required for a snubber capacitor of the GTO to be charged to one half of the GTO anode voltage.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-16 | 1986-11-15 | 1987-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-16 | 1990-11-15 | 1991-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-16 | 1994-11-15 | 1995-05-17 | $7700.00 | Window Closed / Lapsed |