Patent US3825814A successfully refreshed from Google Patents.
US3825814A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Active filter for the input harmonic current of static power converters
Assignee: Westinghouse Electric Corp
•
Filing: 1973-05-29
•
Granted: 1974-07-23
•
Expires: 1993-05-29
Abstract
Abstract An active filter for the input harmonic currents of static power converters comprising an active harmonic voltage generator connected in series with a passive reactive element, the series combination being connected across the converter input terminals. The passive reactive element is such that essentially the fullline voltage appears across the passive reactive element whereby the volt-ampere rating of the active harmonic voltage generator can be materially reduced.
Inventors
- 👤 B Pelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:53
CPC Classifications
H; H04; H04B; H04B15/00; H04B15/02; H02; H02M; H02M1/00; H02M1/14; H02M1/15
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
168 words
In an electrical power system for supplying power from an electrical source section to a load section and wherein said load section generates an electrical ripple to which the source section is subject in the absence of filtering, the combination of power conductors connecting said source section to said load section, an active filter interposed between said sections and comprising a controllable generator connected across said power conductors and responsive to a variable of said electrical ripple for generating a synthetic ripple corresponding to said electrical ripple, said synthetic ripple opposing and substantially eliminating the effect of the electrical ripple on said source section, and a reactive element connected in series with said controllable generator across said power conductors, the reactive element having an impedance value with respect to said source section such that it supports substantially the fullline voltage and prevents the controllable generator in series with it from being exposed to substantially the full-line voltage, whereby the volt-ampere rating of said controllable generator may be reduced.
Claim 2
Dependent Claim
168 words
In an electrical power system for supplying power from an electrical source section to a load section and wherein said load section generates an electrical ripple to which the source section is subject in the absence of filtering, the combination of power conductors connecting said source section to said load section, an active filter interposed between said sections and comprising a controllable generator connected across said power conductors and responsive to a variable of said electrical ripple for generating a synthetic ripple corresponding to said electrical ripple, said synthetic ripple opposing and substantially eliminating the effect of the electrical ripple on said source section, and a reactive element connected in series with said controllable generator across said power conductors, the reactive element having an impedance value with respect to said source section such that it supports substantially the fullline voltage and prevents the controllable generator in series with it from being exposed to substantially the full-line voltage, whereby the volt-ampere rating of said controllable generator may be reduced.
Claim 3
Dependent Claim
17 words
The power system of claim 1 including means for powering said controllable generator from said source section.
Claim 4
Dependent Claim
27 words
The power system of claim 1 wherein said reactive element comprises an L-C circuit substantially tuned to the line frequency of power supplied from said source section.
Claim 5
Dependent Claim
32 words
The combination of claim 1 wherein said reactive element comprises a capacitor which presents a high impedance to power supplied from said source section at the line frequency of said source section.
Claim 6
Dependent Claim
69 words
The power system of claim 1 wherein said controllable generator comprises an electric energy storage means, and switching means operable in a first mode for connecting said storage means to increase said synthetic ripple magnitude and in a second mode for connecting said storage means to decrease said synthetic ripple magnitude, whereby the average value of said synthetic ripple is regulated to the same value as said electrical ripple.
Claim 7
Dependent Claim
14 words
The power system of claim 5 wherein said energy storage means comprises a capacitor.
Claim 8
Dependent Claim
52 words
The power system of claim 6 wherein said capacitor is arranged and connected with said switching means in a bridge configuration connected in series across said power conductors with said reactive element, and means controlling said switching means to regulate said synthetic ripple to essentially the same value as said electrical ripple.
Claim 9
Dependent Claim
88 words
The power system of claim 5 wherein said electrical source section generates a fundamental voltage Vf and said load section generates a ripple voltage Vh, said means for controlling the switching means including apparatus for filtering the voltage Vh from the fundamental voltage Vf having the ripple voltage Vh superimposed thereon, means for inverting the filtered ripple voltage, and means responsive to said inverted ripple voltage for generating an inverted synthetic ripple essentially equal to but opposite in phase to the ripple voltage generated by said load section.
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) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |