US4244015A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse width modulated inverter
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1979-05-24
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Granted: 1981-01-06
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Expires: 1999-05-24
Abstract
Abstract Apparatus for chopping DC power at a high frequency, for example 20 kHz, such high frequency being pulse-width modulated by a lower power frequency source at the desired power frequency. The pulse width modulation is servo controlled through current and voltage feedback to cause the current delivered to a load impedance to be in phase with a reference to power frequency oscillator and to control the output frequency voltage amplitude.
Inventors
- 👤 Ronald F. Beebe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:18
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/4807
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
174 words
Apparatus for inverting DC power into power at an alternating power frequency comprising: an oscillator at said power frequency; a high frequency oscillator for generating signals at a frequency substantially higher than said power frequency; a pulse width modulator connected to receive signals from said high frequency oscillator and having at least two signal inputs for receiving modulating signals; means for rectifying the output of said power frequency oscillator; means for applying said rectified power frequency oscillator signal to one of said signal inputs to said modulator; a DC source of power; means connected to be responsive to the output of said pulse width modulator for switching said DC at said high frequency to produce a train of pulse width modulated power pulses; means connected to said source of power frequency to switch said train of power pulses back and forth between opposite polarities in synchronism with the polarity of said power frequency oscillator; and means for removing frequencies at said high frequency from said train of power pulses to produce a load voltage.
Claim 2
Dependent Claim
174 words
Apparatus for inverting DC power into power at an alternating power frequency comprising: an oscillator at said power frequency; a high frequency oscillator for generating signals at a frequency substantially higher than said power frequency; a pulse width modulator connected to receive signals from said high frequency oscillator and having at least two signal inputs for receiving modulating signals; means for rectifying the output of said power frequency oscillator; means for applying said rectified power frequency oscillator signal to one of said signal inputs to said modulator; a DC source of power; means connected to be responsive to the output of said pulse width modulator for switching said DC at said high frequency to produce a train of pulse width modulated power pulses; means connected to said source of power frequency to switch said train of power pulses back and forth between opposite polarities in synchronism with the polarity of said power frequency oscillator; and means for removing frequencies at said high frequency from said train of power pulses to produce a load voltage.
Claim 3
Dependent Claim
45 words
Apparatus as recited in claim 1 and further comprising an electrical load; means for sensing and producing a signal representative of the current delivered to said load; and means for connecting said current signal to one of said modulating inputs of said pulse width modulator.
Claim 4
Dependent Claim
70 words
Apparatus as recited in claim 2 and further comprising: means for sensing and producing a signal representative of the peaks of voltage delivered to said load; a multiplier connected between said power frequency oscillator and the input of said modulator, said modulator being connected to said last named means for sensing and producing a signal to control the amplitude of signal delivered by said power frequency oscillator to said modulator.
Claim 5
Dependent Claim
22 words
Apparatus as recited in claim 3 and further comprising apparatus connected to increase the voltage of said high frequency pulsed power train.
Claim 6
Dependent Claim
81 words
Apparatus as recited in claims 3 or 4 and further comprising means for biasing and poling the respective voltages applied to the input of said modulator to cause the current applied to said load to track the wave form of said power frequency oscillator and to cause the voltage wave form applied to said load to have a controlled peak value and to be of a wave form to cause said current to track the voltage of said power frequency oscillator.
References Cited (Backward Citations)
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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) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |