US4935859A
Expired / Lapsed
US
⏱️ 0.0 years remaining
PWM inverter circuit having a filtered fundamental feedback DC link variation circuit
Assignee: Sundstrand Corp
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Filing: 1989-10-13
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Granted: 1990-06-19
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Expires: 2009-10-13
Abstract
Abstract This invention relates to a VSCF system for aircraft power generation having a DC source, the DC source producing a substantially constant voltage DC signal. An inverter is coupled to the DC source and receives the DC signal, applying a PWM pattern of switching transients to the DC signal to produce an AC signal from the DC signal. The subject invention contemplates the addition of a feedback circuit which comprises a transformer providing an inductive coupling between the AC signal at a point of regulation and the DC signal at a point between the DC source and the inverter to eliminate short duration switching transients in the PWM pattern. Modulation of the DC signal allows short duration switching transients in the PWM pattern to be lengthened, thereby avoiding physical minimum time switching limitations in the switches of the inverter. Feedback of the AC signal allows inverter frequency to be changed while maintaining synchronization between the DC signal modulation and PWM pattern fed to the inverter.
Inventors
- 👤 Maurice A. Kirchberg
- 👤 Alexander Cook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:14
CPC Classifications
H; H02; H02M; H02M5/00; H02M5/02; H02M5/04; H02M5/22; H02M5/25; H02M5/27; H02M5/272
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
58 words
An AC power source, comprising: converter means for receiving a DC signal and applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal; and feedback means for receiving said AC signal, said feedback means modulating said DC signal to eliminate short duration switching transients in said PWM pattern.
Claim 2
Dependent Claim
58 words
An AC power source, comprising: converter means for receiving a DC signal and applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal; and feedback means for receiving said AC signal, said feedback means modulating said DC signal to eliminate short duration switching transients in said PWM pattern.
Claim 3
Dependent Claim
37 words
The AC source as recited in claim 1 wherein said DC signal is produced by means for producing a wild frequency AC signal coupled to means for rectifying said wild frequency AC signal into said DC signal.
Claim 4
Dependent Claim
56 words
The AC power source as recited in claim 2 wherein said means for applying a PWM pattern comprises: (a) inverter means responsive to said DC signal and an inverter control output signal to provide a controlled inverter output pattern signal; and (b) inverter control means to provide said inverter control output signal to said inverter means.
Claim 5
Dependent Claim
46 words
The AC power source as recited in claim 3 wherein said feedback means comprises a transformer which provides an inductive coupling between said AC signal at a point of regulation and said DC signal at a point between said means for rectifying and said inverter means.
Claim 6
Dependent Claim
18 words
The AC power source as recited in claim 4 wherein said AC signal is provided to electrical loads.
Claim 7
Dependent Claim
21 words
The AC power source as recited in claim 5 wherein said inverter means is controlled in response to said AC signal.
Claim 8
Dependent Claim
22 words
The AC power source is recited in claim 6 wherein said feedback means is coupled to said AC signal via a transformer.
Claim 9
Dependent Claim
76 words
In a VSCF system having a DC source, said DC source producing a substantially constant voltage DC signal and inverter means for receiving said DC signal and applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal, and AC feedback modulator, comprising: feedback means for receiving said AC signal, said feedback means modulating said DC signal to eliminate short duration switching transients in said PWM pattern.
Claim 10
Dependent Claim
76 words
In a VSCF system having a DC source, said DC source producing a substantially constant voltage DC signal and inverter means for receiving said DC signal and applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal, and AC feedback modulator, comprising: feedback means for receiving said AC signal, said feedback means modulating said DC signal to eliminate short duration switching transients in said PWM pattern.
Claim 11
Dependent Claim
41 words
The AC feedback modulator as recited in claim 8 wherein said feedback means provides an inductive coupling between said AC signal at a point of regulation and said DC signal at a point between means for rectifying and said inverter means.
Claim 12
Dependent Claim
26 words
The AC feedback modulator as recited in claim 9 wherein said inverter means is responsive to an inverter control output signal to provide said AC signal.
Claim 13
Dependent Claim
36 words
The AC feedback modulator as recited in claim 10 wherein said DC source comprises means to provide a wild frequency AC signal and said means to rectify said wild frequency AC signal into said DC signal.
Claim 14
Dependent Claim
32 words
The AC feedback modulator as recited in claim 11 wherein said inverter control means comprises means responsive to said AC signal to provide said inverter control output signal to said inverter means.
Claim 15
Dependent Claim
21 words
The AC feedback modulator as recited in claim 12 wherein said AC signal is filtered to produce a filtered AC signal.
Claim 16
Dependent Claim
21 words
The AC feedback modulator as recited in claim 13 wherein said filtered AC signal is provided to said point of regulation.
Claim 17
Independent Claim
65 words
A method for providing AC power, comprising the steps of: receiving a DC signal; applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal from said DC signal; receiving said AC signal into a feedback means; and modulating said DC signal with said feedback means to eliminate short duration switching transients in said PWM pattern.
Claim 18
Independent Claim
65 words
A method for providing AC power, comprising the steps of: receiving a DC signal; applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal from said DC signal; receiving said AC signal into a feedback means; and modulating said DC signal with said feedback means to eliminate short duration switching transients in said PWM pattern.
Claim 19
Dependent Claim
36 words
The method as recited in claim 15 wherein said DC signal is provided by means for producing a wild frequency AC signal coupled to means for rectifying said wild frequency AC signal into said DC signal.
Claim 20
Dependent Claim
29 words
The method as recited in claim 16 wherein inverter control means provides an inverter control output signal to inverter means to produce said AC signal from said DC signal.
Claim 21
Dependent Claim
29 words
The method as recited in claim 17 wherein said feedback means varies a voltage of said DC signal to eliminate said short duration switching transients in said PWM pattern.
Claim 22
Dependent Claim
40 words
The method as recited in claim 18 wherein said feedback means provides an inductive coupling between said AC signal at a point of regulation and said DC signal at a point between said means for rectifying and said inverter means.
Claim 23
Dependent Claim
18 words
The method as recited in claim 19 wherein said AC signal is filtered and provided to electrical loads.
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) | 1993-06-18 | 1993-12-18 | 1994-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-18 | 1997-12-18 | 1998-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-18 | 2001-12-18 | 2002-06-19 | $7700.00 | Window Closed / Lapsed |