Patent US3886433A successfully refreshed from Google Patents.
US3886433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Converter control system with tapped transformer providing constant no-load secondary voltage
Assignee: Hitachi Ltd
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Filing: 1973-08-08
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Granted: 1975-05-27
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Expires: 1993-08-08
Abstract
Abstract A tapped transformer is inserted between an inverter connected to a DC transmission line and an AC system, the transformer being so controlled as to maintain a constant no-load secondary voltage. An inverter is so controlled that if DC current therein is below a rated value thereof, the DC voltage is maintained constant, whereas the extinction angle is maintained constant in the event of the DC current exceeding the rated value. It is further so controlled that in the event that a sudden change in the voltage in the AC system is detected, the extinction angle of the inverter is increased.
Inventors
- 👤 Atsumi Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:04
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/02; H02M7/04; H02M7/12; H02M7/145; H02M7/155; H02M7/162; H02M7/1623; H02M7/1626; G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/14; G05F1/147; G05F1/153; H02M7/42; H02M7/44; H02M7/48; H02M7/505; H02M7/515; H02M7/525
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
186 words
In a converter control system applied to a system comprising a converter connected to a DC line and a tapped transformer for connecting said converter to an AC system; the improvement comprising a circuit for generating a reference voltage varying with the position of said tap of said transformer, a circuit for generating a voltage proportional to the primary voltage of the transformer, first means for comparing the voltages of said two circuits and controlling the position of the tap of said transformer, a circuit for generating a voltage corresponding to the controlling delay angle required for maintaining constant the terminal voltage on the DC side of said converter depending on the value of direct current flowing in said converter, a circuit for generating a voltage corresponding to the controlling delay angle required for maintaining constant the extinction angle of said converter depending on the value of the direct current flowing in said converter, and second means for selecting one of the voltages generated by last-mentioned two circuits and applying a firing pulse or a controlling delay angle corresponding to said selected voltage to said converter.
Claim 2
Dependent Claim
186 words
In a converter control system applied to a system comprising a converter connected to a DC line and a tapped transformer for connecting said converter to an AC system; the improvement comprising a circuit for generating a reference voltage varying with the position of said tap of said transformer, a circuit for generating a voltage proportional to the primary voltage of the transformer, first means for comparing the voltages of said two circuits and controlling the position of the tap of said transformer, a circuit for generating a voltage corresponding to the controlling delay angle required for maintaining constant the terminal voltage on the DC side of said converter depending on the value of direct current flowing in said converter, a circuit for generating a voltage corresponding to the controlling delay angle required for maintaining constant the extinction angle of said converter depending on the value of the direct current flowing in said converter, and second means for selecting one of the voltages generated by last-mentioned two circuits and applying a firing pulse or a controlling delay angle corresponding to said selected voltage to said converter.
Claim 3
Dependent Claim
42 words
A converter control system according to claim 1, further comprising third means for enlarging the controlling angle of advance of said converter in response to the voltage proportional to the rate of a sudden change in the voltage of said AC system.
Claim 4
Dependent Claim
159 words
A converter control system for a DC power transmission system comprising a converter having its DC terminals connected to a DC line through at least a DC reactor and its AC terminals connected to an AC system Through a tapped transformer, the converter control system including means for controlling the tap of said transformer to make the no-load voltage on the secondary side of said transformer constant regardless of voltage variations in said AC system, first regulator means providing an output for adjusting the controlling delay angle of said converter to make the DC terminal voltage of said converter constant, second regulator means providing an output for adjusting the controlling delay angle of said converter to make the extinction angle of said converter constant, selecting circuit means for selecting one of the outputs of said first and second regulator means, and pulse phase shifter means for generating a firing pulse corresponding to an output from said selecting circuit means.
Claim 5
Dependent Claim
159 words
A converter control system for a DC power transmission system comprising a converter having its DC terminals connected to a DC line through at least a DC reactor and its AC terminals connected to an AC system Through a tapped transformer, the converter control system including means for controlling the tap of said transformer to make the no-load voltage on the secondary side of said transformer constant regardless of voltage variations in said AC system, first regulator means providing an output for adjusting the controlling delay angle of said converter to make the DC terminal voltage of said converter constant, second regulator means providing an output for adjusting the controlling delay angle of said converter to make the extinction angle of said converter constant, selecting circuit means for selecting one of the outputs of said first and second regulator means, and pulse phase shifter means for generating a firing pulse corresponding to an output from said selecting circuit means.
Claim 6
Dependent Claim
59 words
A converter control system according to claim 3, further including detection circuit means for detecting a deviation from a reference level for the secondary voltage of said transformer, the deviation being caused by a sudden voltage variation in said AC system, and advance circuit means for advancing the controlling delay angle of said converter according to the detected deviation.
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) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |