US4430697A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for starting a parallel-tuned current fed inverter
Assignee: Westinghouse Electric Corp
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Filing: 1982-03-18
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Granted: 1984-02-07
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Expires: 2002-03-18
Abstract
Abstract A high frequency current-fed inverter of the series/parallel compensated type is started directly with the main thyristors of the inverter by charging the series capacitor through the input inductor of the DC supply during a first time interval with one pole, by discharging the same during a second time interval with the other pole, then passing to free-running operation at an initial frequency from which load operation can begin. The first and second time intervals are established while a constant DC voltage is being applied so that commutation of the outgoing thyristor is insured. DC voltage regulation is eliminated as soon as the free-running operation has been initiated.
Inventors
- 👤 Harold A. Steinbruegge
- 👤 Chuck F. Der
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:35
CPC Classifications
H; H02; H02M; H02M5/00; H02M5/40; H02M5/42; H02M5/44; H02M5/443; H02M5/45; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/505; H02M7/515; H02M7/517
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
176 words
A method of starting a high frequency (HF) thyristor-controlled inverter having a capacitor in series with a parallel compensated load under a DC voltage applied through an inductor element, comprising the steps of: applying said DC voltage to said inductor element and said series capacitor by firing complementary thyristors of one pole of said inverter to conduct during a first time interval sufficient to establish a first predetermined minimum voltage across said series-capacitor, said first minimum voltage being sufficient to commutate said complementary thyristors of one pole; firing complementary thyristors of the other pole of said inverter at the end of said first time interval to conduct during a second predetermined time interval sufficient to establish a second predetermined minimum voltage across said series-capacitor, said second minimum voltage being sufficient to commutate said complementary thyristors of the other pole; and firing said thyristors of said inverter from at least the end of said second time interval in alternate succession at a predetermined free-running frequency of said HF inverter with increasing participation of said parallel compensated load.
Claim 2
Independent Claim
176 words
A method of starting a high frequency (HF) thyristor-controlled inverter having a capacitor in series with a parallel compensated load under a DC voltage applied through an inductor element, comprising the steps of: applying said DC voltage to said inductor element and said series capacitor by firing complementary thyristors of one pole of said inverter to conduct during a first time interval sufficient to establish a first predetermined minimum voltage across said series-capacitor, said first minimum voltage being sufficient to commutate said complementary thyristors of one pole; firing complementary thyristors of the other pole of said inverter at the end of said first time interval to conduct during a second predetermined time interval sufficient to establish a second predetermined minimum voltage across said series-capacitor, said second minimum voltage being sufficient to commutate said complementary thyristors of the other pole; and firing said thyristors of said inverter from at least the end of said second time interval in alternate succession at a predetermined free-running frequency of said HF inverter with increasing participation of said parallel compensated load.
Claim 3
Dependent Claim
19 words
The method of claim 1 with said DC voltage being maintained constant during said first and second time intervals.
Claim 4
Dependent Claim
131 words
Apparatus for starting a thyristor-controlled high frequency (HF) inverter supplied with DC voltage through an inductor element and having a capacitor in series with a parallel compensated load, comprising: first means initiated at an initial instant for firing complementary thyristors associated with one pole of said inverter; second means initiated after a first predetermined time interval from said initial instant for firing complementary thyristors associated with the other pole of said inverter; third means initiated after a second predetermined time interval immediately following said first time interval for firing said complementary thyristor associated with one pole of said inverter; and timing means responsive to initiation of said third means for alternately forming said other and said one pole complementary thyristors as a predetermined initial switching rate of operation for said inverter.
Claim 5
Dependent Claim
131 words
Apparatus for starting a thyristor-controlled high frequency (HF) inverter supplied with DC voltage through an inductor element and having a capacitor in series with a parallel compensated load, comprising: first means initiated at an initial instant for firing complementary thyristors associated with one pole of said inverter; second means initiated after a first predetermined time interval from said initial instant for firing complementary thyristors associated with the other pole of said inverter; third means initiated after a second predetermined time interval immediately following said first time interval for firing said complementary thyristor associated with one pole of said inverter; and timing means responsive to initiation of said third means for alternately forming said other and said one pole complementary thyristors as a predetermined initial switching rate of operation for said inverter.
Claim 6
Dependent Claim
26 words
The apparatus of claim 3 with said first and second predetermined time intervals each being of a duration sufficient to insure commutation of a conducting thyristor.
Claim 7
Dependent Claim
52 words
The apparatus of claim 3 with said DC voltage being provided by a direct current voltage link through voltage regulator means operative to provide a constant DC voltage, said voltage regulator means being enabled before said initial instant, and being disabled at least at the end of said second predetermined time interval.
Claim 8
Dependent Claim
44 words
The apparatus of claim 5 with means for controlling said timing means to regulate the switching rate of operation of said inverter as a function of the load, said controlling means being operative after at least the end of said second predetermined time interval.
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) | 1987-02-06 | 1987-08-08 | 1988-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-06 | 1991-08-08 | 1992-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-06 | 1995-08-08 | 1996-02-07 | $7700.00 | Window Closed / Lapsed |