US3825815A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical power system
Assignee: Westinghouse Electric Corp
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Filing: 1973-06-12
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Granted: 1974-07-23
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Expires: 1993-06-12
Abstract
Abstract Active power filters interposed between an electrical power source section and a load section for generating a synthetic ripple which opposes and effectively eliminates an electrical ripple generated in one of the sections, either the source or the load. In the preferred embodiments of the invention, the synthetic ripple is generated by means of static semiconductor switches from direct current or direct voltage storage elements such as inductors or capacitors, the charge on these elements being obtained and maintained from the power source by appropriate control, and static semiconductor switches rated to handle only the ripple components. The active filters that are described herein have nearly an ideal characteristic. That is, they allow only the fundamental component of the input waveform to pass to the output, without appreciable attenuation, while rejecting all other components regardless of their frequency and independently of whether they are generated by the power source or the load. As compared to prior art filters employing some form of controllable attenuator, the filters of the present invention have substantially higher efficiency and appreciable weight and size reductions over conventional passive L-C filters.
Inventors
- 👤 L Gyugyi
- 👤 E Stacey
- 👤 E Strycula
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:49
CPC Classifications
H; H04; H04B; H04B15/00; H04B15/02; H02; H02M; H02M1/00; H02M1/14; H02M1/15
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
242 words
In an electrical power system for supplying power from an electrical source section to a load section, first and second lines connecting the output of said source section to the input of said load section, one of said sections generating an electrical ripple current to which the other section is subject in the absence of filtering, and an active filter intErposed between said sections and comprising a controllable generator powered from said source and responsive to a variable of said electrical ripple current for generating a synthetic ripple corresponding to said electrical ripple current, said controllable generator comprising inductance means and switching means, said inductance means being arranged and connected with said switching means in a bridge configuration coupled to at least one of said lines, said switching means being operable in a first mode in response to said electrical ripple current exceeding a predetermined magnitude in the positive-going direction and in a second mode in response to said electrical ripple current dropping below a particular magnitude in the negative-going direction, said said switching means in the first mode connecting said inductance means to increase said synthetic ripple magnitude and in the second mode connecting said inductance means to decrease said synthetic ripple magnitude, whereby said synthetic ripple is regulated to the same magnitude as said electrical ripple current, said synthetic ripple opposing and substantially eliminating the effect of the electrical ripple current on said other section without any substantial power loss.
Claim 2
Dependent Claim
242 words
In an electrical power system for supplying power from an electrical source section to a load section, first and second lines connecting the output of said source section to the input of said load section, one of said sections generating an electrical ripple current to which the other section is subject in the absence of filtering, and an active filter intErposed between said sections and comprising a controllable generator powered from said source and responsive to a variable of said electrical ripple current for generating a synthetic ripple corresponding to said electrical ripple current, said controllable generator comprising inductance means and switching means, said inductance means being arranged and connected with said switching means in a bridge configuration coupled to at least one of said lines, said switching means being operable in a first mode in response to said electrical ripple current exceeding a predetermined magnitude in the positive-going direction and in a second mode in response to said electrical ripple current dropping below a particular magnitude in the negative-going direction, said said switching means in the first mode connecting said inductance means to increase said synthetic ripple magnitude and in the second mode connecting said inductance means to decrease said synthetic ripple magnitude, whereby said synthetic ripple is regulated to the same magnitude as said electrical ripple current, said synthetic ripple opposing and substantially eliminating the effect of the electrical ripple current on said other section without any substantial power loss.
Claim 3
Dependent Claim
14 words
The combination of claim 1 wherein said bridge configuration is connected across said lines.
Claim 4
Dependent Claim
25 words
The combination as in claim 1 including an inductor in one of said lines and wherein said bridge configuration is in shunt with said inductor.
Claim 5
Dependent Claim
65 words
The combination as in claim 1 wherein said electrical source section generates a fundamental voltage Vf having superimposed thereon a ripple voltage Vr, said means controlling the switching means including apparatus for comparing a voltage essentially the same as said fundamental voltage Vf with said fundamental voltage having superimposed thereon the ripple voltage Vr to derive an error signal Ve for controlling said switching means.
Claim 6
Dependent Claim
25 words
The combination as in claim 4 wherein said error signal Ve is proportional to the difference between the sum of (Vf + Vr) and Vf.
Claim 7
Dependent Claim
22 words
The combination as in claim 5 including means for modifying said error signal to compensate for internal losses in said controllable generator.
Claim 8
Dependent Claim
48 words
The combination as in claim 6 wherein said means for modifying the error signal provides energy to the controllable generator in the form of Vf X If'' where If'' is that component of current necessary to maintain an essentially constant current across said inductor in the controllable generator.
Claim 9
Dependent Claim
65 words
The combination as in claim 7 wherein the current flowing through said controllable generator is Io and the error signal is modified to compensate for losses by comparing the peak value of Io with the peak value of the synthetic ripple current Ir, and including means for modulating the voltage across the controllable generator with the result of said comparison to compensate for said losses.
Claim 10
Dependent Claim
241 words
In an electrical power system for supplying power from an electrical source section to a load section, first and second lines connecting the output of said source section to the input of said load section, one of said sections generating an electrical ripple voltage to which the other section is subject in the absence of filtering, and an active filter interposed between said sections and comprising a controllable generator powered from said source and responsive to a variable of said electrical ripple voltage for generating a synthetic ripple corresponding to said electrical ripple voltage, said controllable generator comprising capacitance means, and switching means, said capacitance means being arranged and connected with said switching means in a bridge configuration coupled to at least one of said lines, said switching means being operable in a first mode in response to said electrical ripple voltage exceeding a predetermined magnitude in The positive-going direction and in a second mode in response to said electrical ripple voltage dropping below a particular magnitude in the negative-going direction, said switching means in the first mode connecting said capacitance means to increase said synthetic ripple magnitude and in the second mode connecting said capacitance means to decrease said synthetic ripple magnitude, whereby said synthetic ripple is regulated to the same magnitude as said electrical ripple voltage, said synthetic ripple opposing and substantially eliminating the effect of the electrical ripple voltage on said other section without any substantial power loss.
Claim 11
Dependent Claim
241 words
In an electrical power system for supplying power from an electrical source section to a load section, first and second lines connecting the output of said source section to the input of said load section, one of said sections generating an electrical ripple voltage to which the other section is subject in the absence of filtering, and an active filter interposed between said sections and comprising a controllable generator powered from said source and responsive to a variable of said electrical ripple voltage for generating a synthetic ripple corresponding to said electrical ripple voltage, said controllable generator comprising capacitance means, and switching means, said capacitance means being arranged and connected with said switching means in a bridge configuration coupled to at least one of said lines, said switching means being operable in a first mode in response to said electrical ripple voltage exceeding a predetermined magnitude in The positive-going direction and in a second mode in response to said electrical ripple voltage dropping below a particular magnitude in the negative-going direction, said switching means in the first mode connecting said capacitance means to increase said synthetic ripple magnitude and in the second mode connecting said capacitance means to decrease said synthetic ripple magnitude, whereby said synthetic ripple is regulated to the same magnitude as said electrical ripple voltage, said synthetic ripple opposing and substantially eliminating the effect of the electrical ripple voltage on said other section without any substantial power loss.
Claim 12
Dependent Claim
15 words
The combination as in claim 9 wherein said bridge configuration is connected across said lines.
Claim 13
Dependent Claim
28 words
The combination as in claim 10 wherein said bridge configuration is connected to one of said lines in series with said electrical source section and said load section.
Claim 14
Dependent Claim
66 words
The combination as in claim 9 wherein said electrical source section generates a fundamental voltage Vf having superimposed thereon a ripple voltage Vr, said means for controlling the switching means including apparatus for comparing a voltage essentially the same as the fundamental voltage Vf with said fundamental voltage having superimposed thereon the ripple voltage Vr to derive an error signal Ve for controlling said switching means.
Claim 15
Dependent Claim
25 words
The combination as in claim 12 wherein said error signal Ve is proportional to the difference between the sum of (Vf + Vr) and Vf.
Claim 16
Dependent Claim
22 words
The combination as in claim 13 including means for modifying said error signal to compensate for internal losses in said controllable generator.
Claim 17
Dependent Claim
48 words
The combination as in claim 14 wherein said means for modifying the error signal provides energy to the controllable generator in the form of Vf X If'' where If'' is that component of current necessary to maintain an essentially constant voltage across said capacitor in the controllable generator.
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 |