US3611097A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital control system for ac to dc power conversion apparatus
Assignee: General Electric Co
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Filing: 1970-02-05
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Granted: 1971-10-05
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Expires: 1990-02-05
Abstract
Abstract A digital control system for controlling the conversion of electric power from AC power to DC power for delivery to a load. A digital command signal is compared with a digital feedback signal indicative of motor speed so as to generate a digital error signal. A phase detection circuit examines the three phases of the AC source so as to synchronously load the digital error signal into the digital firing circuit associated with each phase at the appropriate time. The digital firing circuits include a plurality of reversible counters which count up during one portion of an excitation cycle and count down for another portion of an excitation cycle. When counting up, if a reversible counter reaches a preset number, a firing pulse is generated for a positively poled SCR. On the other hand, if the reversible counter is counting down, when the counter reaches a preset number, a firing pulse is generated for a negatively poled SCR.
Inventors
- 👤 John A Joslyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:40
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/08; H02M1/084; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/292; H02P7/293; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/911; Y10S388/917
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
168 words
A digital control system for controlling the flow of power from an AC source to a load comprising, in combination: a. a set of controllable rectifiers, poled in opposite directions, connected between the AC source and the load; b. a digital error generator responsive to command and feedback signals for generating digital error signals; c. phase detection means operatively coupled to the AC source and responsive thereto to generate a phase output signal at the earliest point in each half cycle of the AC wave at which the respective one of said controllable rectifiers may be permitted to conduct; and d. means having inputs coupled to said digital error generator and said phase detection means and including counter and register circuits responsive to the phase output signal and the error signals to generate a trigger pulse during a predetermined time interval beginning with receipt of the phase output signal, the time of firing within said predetermined time interval being determined by the digital magnitude of the error signal.
Claim 2
Dependent Claim
168 words
A digital control system for controlling the flow of power from an AC source to a load comprising, in combination: a. a set of controllable rectifiers, poled in opposite directions, connected between the AC source and the load; b. a digital error generator responsive to command and feedback signals for generating digital error signals; c. phase detection means operatively coupled to the AC source and responsive thereto to generate a phase output signal at the earliest point in each half cycle of the AC wave at which the respective one of said controllable rectifiers may be permitted to conduct; and d. means having inputs coupled to said digital error generator and said phase detection means and including counter and register circuits responsive to the phase output signal and the error signals to generate a trigger pulse during a predetermined time interval beginning with receipt of the phase output signal, the time of firing within said predetermined time interval being determined by the digital magnitude of the error signal.
Claim 3
Dependent Claim
48 words
The digital control system as recited in claim 1 wherein said counter and register circuits comprise a reversible counter which counts in one direction when an AC source voltage is positive in polarity and in the other direction when when an AC source voltage is negative in polarity.
Claim 4
Dependent Claim
60 words
The digital control system as recited in claim 2 wherein said counter and register circuits produce a firing pulse for said positively poled controllable rectifier when said error counter reaches a predetermined count in the one direction and produces a firing pulse for said negatively poled controllable rectifier when said error counter reaches a predetermined count in the other direction.
Claim 5
Dependent Claim
19 words
The digital control system as recited in claim 1 wherein the combination included a dynamoelectric machine as a load.
Claim 6
Dependent Claim
40 words
The digital control system as recited in claim 1 wherein said phase detection means operates to initiate conduction during the last 120* of each half cycle of the AC input and during the first 60* of the next half cycle.
Claim 7
Independent Claim
120 words
The method of controlling the transfer of power from an AC source to a load comprising the steps of: a. generating an error signal in digital form in response to command and feedback signals; b. sensing the AC wave shape and generating a signal at the first point in each half cycle at which power is permitted to be transferred to the load; c. loading the digital error signal into an error counter in response to the signal of step (b); d. counting the error counter at a predetermined rate from the count of the digital error signal; and e. firing a controllable rectifier connected between the AC source and the load when the error counter reaches a predetermined count.
Claim 8
Independent Claim
120 words
The method of controlling the transfer of power from an AC source to a load comprising the steps of: a. generating an error signal in digital form in response to command and feedback signals; b. sensing the AC wave shape and generating a signal at the first point in each half cycle at which power is permitted to be transferred to the load; c. loading the digital error signal into an error counter in response to the signal of step (b); d. counting the error counter at a predetermined rate from the count of the digital error signal; and e. firing a controllable rectifier connected between the AC source and the load when the error counter reaches a predetermined count.
Claim 9
Dependent Claim
21 words
The method set forth in claim 6 wherein step (b) comprises generating a signal at 120* advance during each half cycle.
Claim 10
Dependent Claim
129 words
A digital firing circuit operative to fire one of a pair of oppositely poled controllable rectifiers connected to an AC source in response to input signals including a digital error signal and phase signal indicating the earliest points within the AC wave form at which the controllable rectifiers can be fired, said digital firing circuit comprising: a. a digital counter having inputs coupled to receive the digital error signal and the phase signal and being responsive to the signals to begin counting upon receipt of the phase signal at a predetermined rate from a base count determined by the digital magnitude of the error signal, and b. means responsive to said digital counter for producing a firing signal when the count of said digital counter reaches a predetermined value.
Claim 11
Dependent Claim
129 words
A digital firing circuit operative to fire one of a pair of oppositely poled controllable rectifiers connected to an AC source in response to input signals including a digital error signal and phase signal indicating the earliest points within the AC wave form at which the controllable rectifiers can be fired, said digital firing circuit comprising: a. a digital counter having inputs coupled to receive the digital error signal and the phase signal and being responsive to the signals to begin counting upon receipt of the phase signal at a predetermined rate from a base count determined by the digital magnitude of the error signal, and b. means responsive to said digital counter for producing a firing signal when the count of said digital counter reaches a predetermined value.
Claim 12
Dependent Claim
45 words
The digital firing circuit recited in claim 8 wherein said digital counter comprises a reversible counter which counts in one direction when an AC source voltage is positive in polarity and counts in the other direction when an AC source voltage is negative in polarity.
Claim 13
Dependent Claim
28 words
The digital firing circuit recited in claim 8 wherein said phase detection means operates to initiate conduction during the last 120* of each polarity of the AC input.
Claim 14
Dependent Claim
51 words
The digital firing circuit recited in claim 9 whereby said sensing means produces a firing signal for the positively poled SCR whenever said digital counter overflows in the aforesaid one direction and produces a firing signal for the negatively poled SCR whenever said digital counter overflows in the aforesaid other direction.
Claim 15
Dependent Claim
18 words
The digital control system according to claim 8 wherein the combination includes a dynamoelectric machine as a load.
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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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |