Patent US4670826A successfully refreshed from Google Patents.
US4670826A
Expired / Lapsed
US
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Control method for cycloconverter and control apparatus therefor
Assignee: Toshiba Mitsubishi Electric Industrial Systems Corp
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Filing: 1985-12-27
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Granted: 1987-06-02
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Expires: 2005-12-27
Abstract
Abstract A control system for a cycloconverter of the circulating current type produces an ac current of a variable frequency. The cycloconverter is configured to connect a power factor compensating capacitor at its receiving-end, thus to control a lagging reactive power due to a circulating current flowing in the cycloconverter so as to cancel a leading reactive power due to the power factor compensating capacitor. Such a control is carried out under the condition of an operation below the rated load. In contrast, under the condition of an operation above the rated load, a control is effected so that the circulating current flowing in the cycloconverter is substantially kept constant.
Inventors
- 👤 Shigeru Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:06
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/66; H02M7/68; H02M7/72; H02M7/75; H02M7/757; H02M7/7575; Y; Y02; Y02E; Y02E60/00; Y02E60/60; Y02P; Y02P80/00; Y02P80/10
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
111 words
A control method for a cycloconverter of the circulating current type comprising the steps of: connecting a power factor compensating capacitor to a receiving end of said cycloconverter; controlling a circulating current flowing in said cycloconverter so that a lagging reactive power of said cycloconverter and a leading reactive power of said power factor compensating capacitor are cancelled with each other until an output current of said cycloconverter reaches a rated load value; and controlling the circulating current flowing in said cycloconverter so that said circulating current is substantially maintained constant regardless of a power factor at said receiving-end after the output current of said cycloconverter exceeds said rated load value.
Claim 2
Dependent Claim
111 words
A control method for a cycloconverter of the circulating current type comprising the steps of: connecting a power factor compensating capacitor to a receiving end of said cycloconverter; controlling a circulating current flowing in said cycloconverter so that a lagging reactive power of said cycloconverter and a leading reactive power of said power factor compensating capacitor are cancelled with each other until an output current of said cycloconverter reaches a rated load value; and controlling the circulating current flowing in said cycloconverter so that said circulating current is substantially maintained constant regardless of a power factor at said receiving-end after the output current of said cycloconverter exceeds said rated load value.
Claim 3
Dependent Claim
177 words
A cycloconverter apparatus comprising: (a) an AC power supply; (b) a cycloconverter of the circulating current type adapted to receive a power fed from said AC power supply; (c) a single-phase or polyphase load adapted to receive a power fed from said cycloconverter; (d) a power factor compensating capacitor connected at a receiving-end of said cycloconverter; (e) controlling means to control an output current supplied to said load of said cycloconverter; (f) outputting means to output a command value to said controlling means, said controlling means operative in response to said command value for controlling a reactive power at said receiving-end of said cycloconverter; and (g) means for changing said command value to said controlling means depending upon the value of said output current of said cycloconverter; wherein said changing means is operative to output the command value of zero when said output current is less than a rated current value, and operative to increase the command value in proportion to the magnitude of the output current when the output current is above said rated current value.
Claim 4
Dependent Claim
177 words
A cycloconverter apparatus comprising: (a) an AC power supply; (b) a cycloconverter of the circulating current type adapted to receive a power fed from said AC power supply; (c) a single-phase or polyphase load adapted to receive a power fed from said cycloconverter; (d) a power factor compensating capacitor connected at a receiving-end of said cycloconverter; (e) controlling means to control an output current supplied to said load of said cycloconverter; (f) outputting means to output a command value to said controlling means, said controlling means operative in response to said command value for controlling a reactive power at said receiving-end of said cycloconverter; and (g) means for changing said command value to said controlling means depending upon the value of said output current of said cycloconverter; wherein said changing means is operative to output the command value of zero when said output current is less than a rated current value, and operative to increase the command value in proportion to the magnitude of the output current when the output current is above said rated current value.
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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) | 1990-06-01 | 1990-12-01 | 1991-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-01 | 1994-12-01 | 1995-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-01 | 1998-12-01 | 1999-06-02 | $7700.00 | Window Closed / Lapsed |