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US3667027A
Expired / Lapsed
US
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Inverter circuit with stabilized frequency under all load conditions
Assignee: BELL ELECTRONIC CORP
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Filing: 1971-03-30
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Granted: 1972-05-30
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Expires: 1991-03-30
Abstract
Abstract An inverter circuit utilizing a saturable core driving transformer to drive the switch elements includes a generator to pass a stabilized frequency square wave to the driving transformer to stabilize the switching frequency of the inverter to match the stabilized frequency of the square wave. Additional switch means coupled to the driving transformer are responsive to the square wave to short circuit, alternately, portions of the driving transformer at points in time at which the square wave changes polarity thereby forcing the flux to reverse and prevent any frequency drift should the feedback current from the output transformer of the inverter exceed the current supplied by the square wave signal. The additional switches also serve to hold the inverter in an off condition by turning both switches on simultaneously.
Inventors
- 👤 Ricky Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:06
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/538; H02M7/5381
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
125 words
An inverter circuit having first and second switching transistors, an output transformer and a driving transformer for converting a d.c. input to an a.c. output, said circuit including in combination: a. generator means connected to pass a frequency stabilized signal to said driving transformer to stabilize the switching frequency of said transistors to match the stabilized frequency of said signal; b. switch means coupled to said driving transformer and responsive to said frequency stabilized signal to short circuit, alternately, portions of said driving transformer and force a flux reversal therein at points in time at which said frequency stabilized signal switches polarity thereby preventing any frequency drift; and c. current feedback means coupled to said driving transformer to provide sufficient power under a load condition.
Claim 2
Dependent Claim
125 words
An inverter circuit having first and second switching transistors, an output transformer and a driving transformer for converting a d.c. input to an a.c. output, said circuit including in combination: a. generator means connected to pass a frequency stabilized signal to said driving transformer to stabilize the switching frequency of said transistors to match the stabilized frequency of said signal; b. switch means coupled to said driving transformer and responsive to said frequency stabilized signal to short circuit, alternately, portions of said driving transformer and force a flux reversal therein at points in time at which said frequency stabilized signal switches polarity thereby preventing any frequency drift; and c. current feedback means coupled to said driving transformer to provide sufficient power under a load condition.
Claim 3
Dependent Claim
29 words
The subject matter of claim 1, in which is said frequency stabilized signal constitutes a square wave of sufficient power to drive the inverter under a no load condition.
Claim 4
Dependent Claim
69 words
The subject matter of claim 2, in which said switch means comprise first and second solid state switches having control terminals for turning them on and off; and wave shaping circuits connected across the output of said generator means for providing triggering signals to said control terminals generated by said square wave to thereby effect conduction of said switches at the crossover points in time of said square wave.
Claim 5
Dependent Claim
40 words
The subject matter of claim 3, including means connected to said control terminals and responsive to a givEn signal to turn both of said solid state switches on simultaneously and thereby shut off said inverter and hold it shut off.
Claim 6
Dependent Claim
22 words
The subject matter of claim 4, in which said given signal is automatically generated in response to an overloading of said inverter.
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) | 1975-05-30 | 1975-11-29 | 1976-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-30 | 1979-11-29 | 1980-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-30 | 1983-11-29 | 1984-05-30 | $7700.00 | Window Closed / Lapsed |