Patent US3863134A successfully refreshed from Google Patents.
US3863134A
Expired / Lapsed
US
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Electric control circuits for a static power converter
Assignee: CGEE ALSTHOM NORTH AMERICA Inc
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Filing: 1973-07-23
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Granted: 1975-01-28
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Expires: 1993-07-23
Abstract
Abstract Improved means is provided for determining the firing angle at which the respective valves of an electric power converter are sequentially fired. The valves have firing means which are activated in turn by a family of firing signals which are periodically generated at equal intervals and in synchronism with the alternating voltage of the a-c system to which the converter is connected. The firing signal generator, which normally runs at a constant frequency synchronized with the alternating voltage and produces firing signals having a constant firing angle Beta , responds to a variable bipolar control signal by changing Beta at a rate that depends on the control signal magnitude and in a sense that depends on its polarity. A beta monitor is provided for producing an angle feedback signal whose magnitude is representative of Beta , and an overriding clamp influences the control signal as a function of any deviation of the angle feedback signal above a preset maximum limit or below a preset minimum limit so as to minimize any excursion of Beta outside a permissible range which is estabilished by these minimum and maximum limits.
Inventors
- 👤 Ernest M Pollard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:53
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/66; H02M7/68; H02M7/72; H02M7/75; H02M7/757; H02M7/7575; Y; Y02; Y02E; Y02E60/00; Y02E60/60
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
283 words
In an electric power delivery system comprising a plurality of controllable electric valves connected between two sets of power conductors, at least one of said sets being assocaited with a polyphase alternating voltage network, said valves being cyclically fired in a predetermined sequence and at firing angles which can be varied to control the flow of power between said sets of conductors, improved means for determining said firing angles comprising: a. a source of a variable bipolar control signal; b. means responsive to said control signal for producing during each cycle of alternating voltage a family of periodic output signals whose timing, relative to recurrent reference points in said cycle, is characterized by a variable electrical angle beta ( Beta ), said output signal producing means being so constructed and arranged that when said control signal is zero and said alternating voltage has a predetermined fundamental frequency the magnitude of Beta is constant and when said control signal has a finite magnitude and said alternating voltage has said predetermined fundamental frequency the magnitude of Beta is changing at a rate that depends on the control signal magnitude and in a sense that depends on its polarity; c. means activated by the respective output signals of said family for firing said valves in sequence; d. means for producing an angle feedback signal whose magnitude is representative of Beta ; and e. clamp means coupled to said source and responsive to said angle feedback signal for influencing said control signal as a function of any deviation of said feedback signal above a preset maximum limit or below a preset minimum limit, said minimum limits thereby establishing a range in which Beta is permitted to vary.
Claim 2
Dependent Claim
283 words
In an electric power delivery system comprising a plurality of controllable electric valves connected between two sets of power conductors, at least one of said sets being assocaited with a polyphase alternating voltage network, said valves being cyclically fired in a predetermined sequence and at firing angles which can be varied to control the flow of power between said sets of conductors, improved means for determining said firing angles comprising: a. a source of a variable bipolar control signal; b. means responsive to said control signal for producing during each cycle of alternating voltage a family of periodic output signals whose timing, relative to recurrent reference points in said cycle, is characterized by a variable electrical angle beta ( Beta ), said output signal producing means being so constructed and arranged that when said control signal is zero and said alternating voltage has a predetermined fundamental frequency the magnitude of Beta is constant and when said control signal has a finite magnitude and said alternating voltage has said predetermined fundamental frequency the magnitude of Beta is changing at a rate that depends on the control signal magnitude and in a sense that depends on its polarity; c. means activated by the respective output signals of said family for firing said valves in sequence; d. means for producing an angle feedback signal whose magnitude is representative of Beta ; and e. clamp means coupled to said source and responsive to said angle feedback signal for influencing said control signal as a function of any deviation of said feedback signal above a preset maximum limit or below a preset minimum limit, said minimum limits thereby establishing a range in which Beta is permitted to vary.
Claim 3
Dependent Claim
96 words
The improvement of claim 1 in which said feedback signal producing means is so constructed and arranged that the magnitude of the angle feedback signal varies with the predicted magnitude of Beta for each consecutive output signal that will in turn cause the next valve firing in said sequence, and said clamp means is operative in response to deviations of said feedback signal beyond said preset limits to influence said control signal in a sense that regulates the operation of said output signal producing means as necessary to minimize excurison of Beta outside said permissible range.
Claim 4
Dependent Claim
73 words
The improvement of claim 1 in which said source includes means for deriving a varIable input signal which depends on the error, if any, between a valve firing angle and a desired angle which is established by a predetermined one of said preset limits, said control signal responding to input signal variations by effecting corrective operation of said output signal producing means which changes Beta as necessary to reduce said error to zero.
Claim 5
Dependent Claim
37 words
The improvement of claim 3 in which said input signal deriving means responds to the difference between the actual magnitude of said angle feedback signal and a desired magnitude that is determined by said predetermined one limit.
Claim 6
Dependent Claim
16 words
The improvement of claim 4 in which said predetermined one limit comprises said preset maximum limit.
Claim 7
Dependent Claim
44 words
The improvement of claim 5 in which said desired magnitude differs from said preset maximum limit by a fixed magnitude which is representative of a relatively small angular margin, said margin ensuring that said desired angle is less than the maximum permissible Beta .
Claim 8
Dependent Claim
107 words
The improvement of claim 1 in which said output signal producing means includes an oscillator whose frequency of operation varies with the magnitude of a frequency determining signal supplied thereto, the operating frequency of said oscillator determining the frequency of said output signals and hence the frequency of the respective valve firings, means for supplying said oscillator with said frequency determining signal whose normal magnitude causes the oscillator to operate at a frequency which is a predetermined harmonic of the fundamental frequency of said alternating voltage, and means for increasing or decreasing the magnitude of said frequency determining signal according to the value of said control signal.
Claim 9
Dependent Claim
93 words
The improvement of claim 7 in which said feedback signal producing means is so constructed and arranged that the magnitude of the angle feedback signal varies with the predicted magnitude of Beta for each consecutive output signal that will in turn cause the next valve firing in said sequence, and said clamp means is operative in response to deviations of said feedback signal beyond said preset limits to influence said control signal in a sense that regulates the frequency of said oscillator as necessary to minimize excursion of Beta outside said permissible range.
Claim 10
Dependent Claim
80 words
The improvement of claim 7 in which said control signal is derived from a bipolar error signal which depends on the difference between actual and desired magnitudes of a selected quantity of the system, and in which compensating means is provided for varying the normal magnitude of said frequency determining signal with variations in the actual fundamental frequency of said alternating voltage so as to keep said output signals synchronized with the alternating voltage whenever said error signal is zero.
Claim 11
Dependent Claim
34 words
The improvement of claim 7 in which said control signal is derived from a bipolar input signal which depends on the difference between actual and desired mangitudes of a selected quantity of the system.
Claim 12
Dependent Claim
81 words
The improvement of claim 10 in which said source comprises means for algebraically summing said input signal and a limit signal which said clamp means supplies in response to deviation of said feedback signal beyond said preset limits, said limit signal being proportional in magnitude to the amount of said deviation and influencing said control signal and hence said frequency determining signal in a sense that regulates the oscillator frequency as necessary to minimize excursion of Beta outside said permissible range.
Claim 13
Dependent Claim
60 words
The improvement of claim 10 including means for providing a bias signal of preselected magnitude, said frequency determining signal comprising the algegraic sum of said control signal and said bias signal, said bias signal being effective when said control signal is zero to cause the oscillator to operate at a frequency which is said predetermined harmonic of said predetermined fundamental.
Claim 14
Dependent Claim
68 words
The improvement of claim 12 in which said source additionally comprises compensating Means for influencing said control signal so as to ensure that said frequency determining signal has a proper magnitude to keep said output signals synchronized with said alternating voltage whenever the actual fundamental frequency of said alternating voltage differs from said predetermined fundamental frequency and the actual magnitude of said selected quantity equals said desired magnitude.
Claim 15
Dependent Claim
53 words
The improvement of claim 1 in which said source comprises means for algebraically summing a variable bipolar input signal and a limit signal which said clamp means supplies in response to said angle feedback signal being beyond said limits, said control signal being representative of the sum of said input and limit signals.
Claim 16
Dependent Claim
79 words
The improvement of claim 14 in which said input signal is derived from a bipolar error signal which depends on the difference between actual and desired magnitudes of a selected quantity of the system, and in which compensating means is provided for ensuring that so long as said limit and error signals are zero said control signal has a proper magnitude to keep Beta constant whenever the actual fundamental frequency of said alternating voltage differs from predetermined fundamental frequency.
Claim 17
Dependent Claim
45 words
The improvement of claim 15 in which said compensating means comprises means for adding to said error signal a signal whose magnitude is the time integral of said error signal, said input signal being dependent on the sum of said error signal and its integral.
Claim 18
Dependent Claim
63 words
The improvement of claim 16 in which said compensating means includes additional means for adding to said error signal a compensating signal which depends on the difference between the actual fundamental fequency of said alternating voltage and said predetermined fundamental frequency, said input signal being dependent on the sum of said compensating signal, said error signal, and the integral of said error signal.
Claim 19
Dependent Claim
98 words
The improvement of claim 1 in which said source includes means for deriving an error signal which depends on the difference between actual and desired magnitudes of a selected quantity of the system and variable gain means for amplifying said error signal, said control signal responding to variations in the amplified error signal by regulating the operation of said output signal producing means as necessary to shift Beta to a value that results in zero error, the gain of said amplifying means being varied as an appropriate function of said angle feedback signal to linearize the regulating action.
Claim 20
Dependent Claim
17 words
The improvement of claim 18 in which said gain varies as approximately the cosecant of Beta .
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) | 1978-01-27 | 1978-07-29 | 1979-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-27 | 1982-07-29 | 1983-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-27 | 1986-07-29 | 1987-01-28 | $7700.00 | Window Closed / Lapsed |