US4680691A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and system for preventing an excessive voltage build-up in a power converter system
Assignee: Toshiba Corp
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Filing: 1986-06-06
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Granted: 1987-07-14
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Expires: 2006-06-06
Abstract
Abstract A synchronous condenser is provided on an AC bus line which is connected to an AC power system via a circuit breaker. The AC bus line and a DC bus line are connected via a power converter system. In such a system, if three conditions: the breaker is opened; the synchronous condenser is under operation; and the power converter operates as an inverter, are met, the power converter is driven into a zero power factor operation, i.e., an operation to cancel a capacitive reactive power on the AC bus line including AC filters in order to prevent the synchronous condenser self-excitation.
Inventors
- 👤 Teruo Yoshino
- 👤 Katsuro Itoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:59
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/36; H02M; H02M7/00; H02M7/66; H02M7/68; H02M7/72; H02M7/75; H02M7/757; H02M7/7575; Y; Y02; Y02E; Y02E60/00; Y02E60/60
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
106 words
A method for operating a power converter connected between a DC bus line and an AC bus line, said AC bus line provided with a synchronous condenser and connected to an AC power system through a breaker, comprising the steps of: detecting whether or not said breaker is opened; detecting whether or not said synchronous condenser is under operation; detecting whether or not said power converter works as inverter; and driving said power converter at a firing angle cancelling a capacitive reactive power of said AC bus line when said breaker is opened, said synchronous condenser is under operation, and said power converter works as inverter.
Claim 2
Independent Claim
106 words
A method for operating a power converter connected between a DC bus line and an AC bus line, said AC bus line provided with a synchronous condenser and connected to an AC power system through a breaker, comprising the steps of: detecting whether or not said breaker is opened; detecting whether or not said synchronous condenser is under operation; detecting whether or not said power converter works as inverter; and driving said power converter at a firing angle cancelling a capacitive reactive power of said AC bus line when said breaker is opened, said synchronous condenser is under operation, and said power converter works as inverter.
Claim 3
Dependent Claim
19 words
A method for operating a power converter according to claim 1, wherein said firing angle is about 90 degrees.
Claim 4
Independent Claim
122 words
A system for operating a power converter connected between a DC bus line and an AC bus line, said AC bus line provided with a synchronous condenser and connected to an AC power system through a breaker, comprising: first means for generating a second signal while said breaker is opened; second means for generating a second signal while said synchronous condenser is under operation; third means for generating a third signal while said power converter works as inverter; and control means for driving said power converter at a predetermined firing angle upon reception of said first, second and third signals thereby consuming on said AC bus line a reactive power sufficient for cancelling a capacitive reactive power of said AC bus line.
Claim 5
Independent Claim
122 words
A system for operating a power converter connected between a DC bus line and an AC bus line, said AC bus line provided with a synchronous condenser and connected to an AC power system through a breaker, comprising: first means for generating a second signal while said breaker is opened; second means for generating a second signal while said synchronous condenser is under operation; third means for generating a third signal while said power converter works as inverter; and control means for driving said power converter at a predetermined firing angle upon reception of said first, second and third signals thereby consuming on said AC bus line a reactive power sufficient for cancelling a capacitive reactive power of said AC bus line.
Claim 6
Dependent Claim
49 words
A system for operating a power converter according to claim 3, wherein: said control means comprises firing angle setting means for outputting a fourth signal corresponding to said predetermined firing angle; and said control means drives said power converter at said predetermined firing angle based on said fourth signal.
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) | 1990-07-13 | 1991-01-12 | 1991-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-13 | 1995-01-12 | 1995-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-13 | 1999-01-12 | 1999-07-14 | $7700.00 | Window Closed / Lapsed |