Patent US4752726A successfully refreshed from Google Patents.
US4752726A
Expired / Lapsed
US
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Reactive power compensation device
Assignee: Toshiba Corp
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Filing: 1987-08-31
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Granted: 1988-06-21
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Expires: 2007-08-31
Abstract
Abstract A reactive power compensation device for a system including an AC power source and a load. The device comprises a first detection circuit for detecting reactive power in the load; a first reactive power compensation circuit, having a reactor, a thyristor and a capacitor, the thyristor being controlled based on the detected reactive power in the load; a second detection circuit for detecting total reactive power in the load and the first compensation circuit; a second reactive power compensation circuit having a self-commutated power converter connected in parallel to the load. The second compensation circuit is controlled to minimize the detected total reactive power in the load and the first compensation circuit.
Inventors
- 👤 Fumio Aoyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:57
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/18; H02J3/1821; H02J3/1835; Y; Y02; Y02E; Y02E40/00; Y02E40/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
A device for compensating for reactive power in a system including an AC power source and a load, the device comprising: means for detecting reactive power in the load; a first reactive power compensation circuit, having a reactor and a thyristor connected in series, and a capacitor connected in parallel to the reactor and the thyristor, the first compensation circuit being connected in parallel to the load, the thyristor being controlled based on the detected reactive power in the load; means for detecting total reactive power in the load and the first compensation circuit; a second reactive power compensation circuit having a self-commutated power converter connected in parallel to the load; and means for controlling the second compensation circuit to minimize the detected total reactive power in the load and the first compensation circuit.
Claim 2
Independent Claim
134 words
A device for compensating for reactive power in a system including an AC power source and a load, the device comprising: means for detecting reactive power in the load; a first reactive power compensation circuit, having a reactor and a thyristor connected in series, and a capacitor connected in parallel to the reactor and the thyristor, the first compensation circuit being connected in parallel to the load, the thyristor being controlled based on the detected reactive power in the load; means for detecting total reactive power in the load and the first compensation circuit; a second reactive power compensation circuit having a self-commutated power converter connected in parallel to the load; and means for controlling the second compensation circuit to minimize the detected total reactive power in the load and the first compensation circuit.
Claim 3
Dependent Claim
25 words
A device according to claim 1, wherein the second reactive power compensation circuit includes a DC capacitor and a gate-turn-off thyristor for pulse-width modulation control.
Claim 4
Independent Claim
129 words
A method of compensating for reactive power in a system including an AC power source and a load, the method comprising steps of: detecting reactive power in the load; compensating for reactive power in the load based on the detected reactive power in the load by a first compensation circuit which has a reactor and a thyristor connected in series, and a capacitor connected in parallel to the reactor and the thyristor; detecting total reactive power in the load and the first compensation circuit; and compensating reactive power in the load and the first compensation circuit based on the detected total reactive power in the load and the first compensation circuit by a second reactive power compensation circuit having a self-commutated power converter connected in parallel to the load.
Claim 5
Independent Claim
129 words
A method of compensating for reactive power in a system including an AC power source and a load, the method comprising steps of: detecting reactive power in the load; compensating for reactive power in the load based on the detected reactive power in the load by a first compensation circuit which has a reactor and a thyristor connected in series, and a capacitor connected in parallel to the reactor and the thyristor; detecting total reactive power in the load and the first compensation circuit; and compensating reactive power in the load and the first compensation circuit based on the detected total reactive power in the load and the first compensation circuit by a second reactive power compensation circuit having a self-commutated power converter connected in parallel to the load.
Claim 6
Dependent Claim
27 words
A method according to claim 3, wherein the steps of compensating reactive power in the load and the first compensation circuit is controlled by pulse-width modulation control.
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) | 1991-06-21 | 1991-12-21 | 1992-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-21 | 1995-12-21 | 1996-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-21 | 1999-12-21 | 2000-06-21 | $7700.00 | Window Closed / Lapsed |