US5072187A
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US
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Method and apparatus for determining the total harmonic distortion and power factor of a non-linear load circuit
Assignee: Hewlett Packard Development Co LP
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Filing: 1990-06-29
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Granted: 1991-12-10
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Expires: 2010-06-29
Abstract
Abstract A method and apparatus for determining the total harmonic distortion and the power factor of a non-linear load circuit coupled to an a.c. power source generating a.c. current and a.c. voltage, the a.c. current input to the load circuit being in phase with the a.c. voltage provided across the load circuit by the a.c. power source. The invention measures the total harmonic distortion of a.c. current and a.c. voltage at the non-linear load circuit and calculates the total harmonic distortion and the power factor as a function of both.
Inventors
- 👤 Marcel Shilo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:46
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/16; G01R23/20; G01R21/00; G01R21/006
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
134 words
An apparatus for determining the power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the non-linear load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, comprising: first means for measuring the total harmonic distortion of a.c. current (THD i ) input to the non-linear load; second means for measuring the total harmonic distortion of a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and means, coupled to the first and second means, for calculating the power factor of the non-linear load circuit as a function of both THD i and THD v .
Claim 2
Independent Claim
134 words
An apparatus for determining the power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the non-linear load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, comprising: first means for measuring the total harmonic distortion of a.c. current (THD i ) input to the non-linear load; second means for measuring the total harmonic distortion of a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and means, coupled to the first and second means, for calculating the power factor of the non-linear load circuit as a function of both THD i and THD v .
Claim 3
Dependent Claim
26 words
An apparatus according to claim 1, wherein the means for calculating the power factor includes means for determining the power factor according to the relationship: ##EQU18##
Claim 4
Dependent Claim
26 words
An apparatus according to claim 1, wherein the means for calculating the power factor includes means for determining the power factor according to the relationship: ##EQU19##
Claim 5
Dependent Claim
28 words
An apparatus according to claim 1, wherein the first means for measuring THD i comprises a harmonic distortion analyzer and an a.c. current probe for detecting a.c. current.
Claim 6
Dependent Claim
28 words
An apparatus according to claim 1, wherein the second means for measuring THD v comprises a harmonic distortion analyzer and an a.c. voltage probe for detecting a.c. voltage.
Claim 7
Dependent Claim
18 words
An apparatus according to claim 1, wherein the means for calculating the power factor comprises a computational unit.
Claim 8
Dependent Claim
18 words
An apparatus according to claim 1, wherein the means for calculating the power factor includes a programmable processor.
Claim 9
Dependent Claim
24 words
An apparatus according to claim 1, further comprising a display connected to the means for calculating the power factor for displaying the power factor.
Claim 10
Dependent Claim
22 words
An apparatus according to claim 1, wherein each of the means is provided in a single piece of programmable electrical test equipment.
Claim 11
Dependent Claim
38 words
An apparatus according to claim 1, further comprising: means, coupled to the first and second means, for calculating total harmonic distortion (THD) of the non-linear load circuit as a function of both THD i and THD v .
Claim 12
Dependent Claim
29 words
An apparatus according to claim 10, wherein the means for calculating the total harmonic distortion (THD) includes means for calculating the total harmonic distortion according to the relationship: ##EQU20##
Claim 13
Dependent Claim
19 words
An apparatus according to claim 10, wherein the means for calculating the total harmonic distortion comprises a computational unit.
Claim 14
Dependent Claim
19 words
An apparatus according to claim 10, wherein the means for calculating the total harmonic distortion includes a programmable processor.
Claim 15
Dependent Claim
26 words
An apparatus according to claim 10, further comprising a display connected to the means for calculating the total harmonic distortion for displaying the total harmonic distortion.
Claim 16
Dependent Claim
22 words
An apparatus according to claim 10, wherein each of the means is provided in a single piece of programmable electrical test equipment.
Claim 17
Independent Claim
132 words
An apparatus for determining the power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the non-linear load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, comprising: first means for measuring the total harmonic distortion of a.c. current (THD i ) input to the non-linear load; second means for measuring the total harmonic distortion of a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and means, coupled to the first and second means, for separating out contributions to an observed power factor provided by circuit components other than the non-linear load circuit.
Claim 18
Independent Claim
132 words
An apparatus for determining the power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the non-linear load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, comprising: first means for measuring the total harmonic distortion of a.c. current (THD i ) input to the non-linear load; second means for measuring the total harmonic distortion of a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and means, coupled to the first and second means, for separating out contributions to an observed power factor provided by circuit components other than the non-linear load circuit.
Claim 19
Dependent Claim
34 words
An apparatus according to claim 16, further comprising means for displaying the power factor of the non-linear load circuit based on contributions to the observed power factor provided only by the non-linear load circuit.
Claim 20
Dependent Claim
34 words
An apparatus according to claim 16, wherein the means for separating includes means for calculating the power factor of the non-linear load circuit as a function of both THD i and THD v .
Claim 21
Dependent Claim
26 words
An apparatus according to claim 18, wherein the means for calculating the power factor includes means for calculating the power factor according to the relationship: ##EQU21##
Claim 22
Dependent Claim
26 words
An apparatus according to claim 18, wherein the means for calculating the power factor includes means for calculating the power factor according to the relationship: ##EQU22##
Claim 23
Independent Claim
151 words
A method of determining power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, the method comprising the steps of: measuring the total harmonic distortion of the a.c. current (THD i ) input to the non-linear load circuit by the power source; measuring the total harmonic distortion of the a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and operating a computational unit in accordance with a predetermined relationship which takes into account both THD i and THD v to determine the power factor (PF) of the non-linear load circuit as a function of both THD i and THD v .
Claim 24
Independent Claim
151 words
A method of determining power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, the method comprising the steps of: measuring the total harmonic distortion of the a.c. current (THD i ) input to the non-linear load circuit by the power source; measuring the total harmonic distortion of the a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and operating a computational unit in accordance with a predetermined relationship which takes into account both THD i and THD v to determine the power factor (PF) of the non-linear load circuit as a function of both THD i and THD v .
Claim 25
Dependent Claim
23 words
A method according to claim 21, wherein the operating step includes the step of calculating the power factor according to the relationship: ##EQU23##
Claim 26
Dependent Claim
23 words
A method according to claim 21, wherein the operating step includes the step of calculating the power factor according to the relationship: ##EQU24##
Claim 27
Dependent Claim
16 words
A method according to claim 21, further comprising the step of displaying the calculated power factor.
Claim 28
Dependent Claim
54 words
A method according to claim 21, further comprising the steps of: operating a computational unit in accordance with a predetermined relationship which takes into account both THD i and THD v to determine the total harmonic distortion (THD) of the non-linear load circuit as a function of both THD i and THD v .
Claim 29
Dependent Claim
25 words
A method according to claim 25, wherein the operating step includes the step of calculating the total harmonic distortion (THD) according to the relationship: ##EQU25##
Claim 30
Dependent Claim
17 words
A method according to claim 25, further comprising the step of displaying the calculated total harmonic distortion.
Claim 31
Independent Claim
128 words
A method of determining power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, the method comprising the steps of: measuring the total harmonic distortion of the a.c. current (THD i ) input to the non-linear load circuit from the a.c. power source; measuring the total harmonic distortion of the a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and separating out contributions to an observed power factor provided by circuit components other than the non-linear load circuit.
Claim 32
Independent Claim
128 words
A method of determining power factor (PF) of a non-linear load circuit coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load circuit, the a.c. current input to the load circuit being substantially in phase with the a.c. voltage supplied across the load circuit by the a.c. power source, the method comprising the steps of: measuring the total harmonic distortion of the a.c. current (THD i ) input to the non-linear load circuit from the a.c. power source; measuring the total harmonic distortion of the a.c. voltage (THD v ) provided across the non-linear load circuit by the a.c. power source; and separating out contributions to an observed power factor provided by circuit components other than the non-linear load circuit.
Claim 33
Dependent Claim
23 words
A method according to claim 28, wherein said separating step includes the step of calculating the power factor according to the relationship: ##EQU26##
Claim 34
Dependent Claim
23 words
A method according to claim 28, wherein said separating step includes the step of calculating the power factor according to the relationship: ##EQU27##
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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) | 1994-12-09 | 1995-06-10 | 1995-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-09 | 1999-06-10 | 1999-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-09 | 2003-06-10 | 2003-12-10 | $7700.00 | Window Closed / Lapsed |