Patent US6080151A successfully refreshed from Google Patents.
US3746966A
Expired / Lapsed
US
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Current converter control system
Assignee: ABB Norden Holding AB
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Filing: 1972-01-20
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Granted: 1973-07-17
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Expires: 1992-01-20
Abstract
Abstract Disclosed herein is a current control system for a static converter. The converter has an inductive load object connected to its DC terminals and has a plurality of controllable rectifiers with a firing pulse generator connected to the rectifiers for supplying firing pulses thereto in a predetermined commutation sequence. The control system has a current sensing device for sensing the DC load current of the converter. A function generator computes, on the basis of this current, during each interval between consecutive firing pulses, a predicted load current value. This predicted value at each moment during one of said intervals corresponds to the load current, which is obtained during the next one of said intervals, if the next firing pulse in the commutation sequence is supplied at that moment. The predicted value is compared with a current reference value. When these two quantitites become equal the next firing pulse is supplied.
Inventors
- 👤 V Torok
- 👤 H Skoog
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:22
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/02; H02M7/04; H02M7/12; H02M7/145; H02M7/155; H02M7/162; H02M7/1623; H02M7/1626; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/292; H02P7/293; Y; Y10; Y10S; Y10S388/00; Y10S388/923; Y10S388/93
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
221 words
A current control system for a converter, said converter having an inductive load object connected to its DC terminals and comprising a plurality of controllable rectifiers and firing pulse generating means connected to the rectifiers for supplying firing pulses for firing of the rectifiers in a predetermined commutation sequence, which control system comprises a. current sensing means for sensing the DC load current of the converter during each time interval between two consecutive firing pulses; b. function generating means supplied with said sensed DC load current, for generating continuously, during at least a part of each of said intervals, on the basis of said sensed current, a prediction quantity, which at each moment corresponds to the DC load current, which is obtained during the next one of said intervals if the next firing pulse in said commutation sequence is supplied at that moment; c. means for generating a current reference quantity corresponding to a desired value of the load current; d. comparing means connected to said function generating means, to said reference quantity generating means and to said firing pulse generating means for comparing said prediction quantity with said current reference quantity and for causing said firing pulse generating means to supply the next firing pulse in said commutating sequence when said predicted quantity and said current reference quantity are equal.
Claim 2
Dependent Claim
221 words
A current control system for a converter, said converter having an inductive load object connected to its DC terminals and comprising a plurality of controllable rectifiers and firing pulse generating means connected to the rectifiers for supplying firing pulses for firing of the rectifiers in a predetermined commutation sequence, which control system comprises a. current sensing means for sensing the DC load current of the converter during each time interval between two consecutive firing pulses; b. function generating means supplied with said sensed DC load current, for generating continuously, during at least a part of each of said intervals, on the basis of said sensed current, a prediction quantity, which at each moment corresponds to the DC load current, which is obtained during the next one of said intervals if the next firing pulse in said commutation sequence is supplied at that moment; c. means for generating a current reference quantity corresponding to a desired value of the load current; d. comparing means connected to said function generating means, to said reference quantity generating means and to said firing pulse generating means for comparing said prediction quantity with said current reference quantity and for causing said firing pulse generating means to supply the next firing pulse in said commutating sequence when said predicted quantity and said current reference quantity are equal.
Claim 3
Dependent Claim
35 words
Control system according to claim 1, which comprises maximum current indicating means for supplying to said function generating means information about the time when the DC load current during the interval has its maximum value.
Claim 4
Dependent Claim
43 words
Control system according to claim 2, in which said maximum current indicating means comprises a transformer having a primary winding connected into the DC load current circuit and generating a secondary voltage, the passage of the secondary voltage through zero constituting said information.
Claim 5
Dependent Claim
31 words
Control system according to claim 1, in which said quantity generated by the function generating means corresponds to the peak value of the DC load current duRing the following commutation interval.
Claim 6
Dependent Claim
52 words
Control system according to claim 4, in which said quantity corresponds to the peak value of the direct current under the present interval at a moment which is half the average length of a commutation interval later than the moment of the peak value of the direct current under the present interval.
Claim 7
Dependent Claim
16 words
Control system according to claim 4, in which said quantity is a linear function of time.
Claim 8
Dependent Claim
47 words
Control system according to claim 6, in which said quantity has a time derivative equal to -8. Delta I/Tn , where Delta I is the peak-to-peak value of the DC load current pulsations during stationary conditions, and where Tn is the average length of a commutation interval.
Claim 9
Dependent Claim
44 words
Control system according to claim 1, in which the system has means to influence said firing pulse generating means for supplying a firing pulse only after the moment of occurrence of the peak value of the DC load current during the present commutation interval.
Claim 10
Dependent Claim
42 words
Control system according to claim 7, in which said quantity corresponds to I + 4 Delta I during a time before the occurrence of the peak value of the load current, where I is the momentary value of the DC load current.
Claim 11
Dependent Claim
128 words
Control system according to claim 1, in which said function generating means generates, at least during part of each commutation interval, a first magnitude which at each moment corresponds to the time-voltage intergral, which, if a commutation had been made at that moment, would have been supplied to the inductance of the DC circuit during the time interval from said moment to the next following load current peak, and includes a first adding means supplied with said first magnitude and, supplied from said current sensing means, with a quantity corresponding to the momentary value of the load current to generate an output quantity corresponding to the sum of these quantities, and in which said output quantity is supplied to said comparing means for comparison with said reference quantity.
Claim 12
Dependent Claim
58 words
Control system according to claim 10, in which said function generating means comprises time determining means for generating, at each moment, a second quantity corresponding to the time to the load current peak of the next following commutation interval and computation means supplied with said second quantity to generate said first quantity in dependence upon said second quantity.
Claim 13
Dependent Claim
80 words
Control system according to claim 11, in which said time determining means comprise first means for generating a third quantity, which, at each moment, corresponds to the time interval between said moment and the moment of occurrence of the load current peak of the present commutation interval, said time determining means also comprising second adding means for adding to said third quantity a fourth quantity corresponding to the time interval between two load current maxima for generating said second quantity.
Claim 14
Dependent Claim
36 words
Control system according to claim 12, in which said first means comprises current derivative sensing means for generating a quantity which corresponds to the time derivative of the load current and which constitutes said third quantity.
Claim 15
Dependent Claim
42 words
Control system according to claim 13, in which said current derivative sensing means comprises a transformer having a primary winding which is connected into the DC load current circuit and the secondary voltage of which is supplied to said second adding means.
Claim 16
Dependent Claim
20 words
Control system according to claim 14, in which said transformer has a core which is provided with an air gap.
Claim 17
Dependent Claim
39 words
Control system according to claim 11, in which said computing means comprises squaring means supplied with said second quantity and generating an output signal corresponding to the square of said second quantity, said output signal constituting said first quantity.
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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) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |