US3700987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse modulation motor control
Assignee: Raytheon Co
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Filing: 1971-03-29
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Granted: 1972-10-24
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Expires: 1991-03-29
Abstract
Abstract A typical alternating current servomotor has two windings displaced 90*; these windings are identified as a reference winding and a control winding. Rotational direction and speed of the motor may be controlled by applying AC voltages of the proper wave form, amplitude and phase relationship to these windings. When controlling the direction of rotation and speed of the motor in accordance with a DC error signal, pulse width modulation techniques are employed. The error signal is compared with a triangular wave function to generate a first and second series of pulses each having a width related to the magnitude of the error signal. These series of pulses are logically combined with a square wave function to produce first and second digital motor energizing signals. The motor energizing signals control a power amplifier switch connected to the windings of the motor to be controlled.
Inventors
- 👤 Charles S Deering
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:49
CPC Classifications
H; H02; H02P; H02P23/00; H02P23/24
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
152 words
A system for controlling the energization of an alternating current load from a DC source in accordance with an error signal comprising: means for comparing a linearly varying periodic function with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, second means for comparing a linearly varying periodic function with said error signal to generate a second series of pulses each having a width related to the magnitude of said error signal, phase selection circuit means for combining each of said series of pulses with a periodically varying function to produce a first and second energizing signal, the phase relationship of said first and second energizing signals controlling the phase energization of said load, and switching means actuated by said energizing signals to connect the DC power source to the load to produce an effective alternating current excitation thereof.
Claim 2
Independent Claim
152 words
A system for controlling the energization of an alternating current load from a DC source in accordance with an error signal comprising: means for comparing a linearly varying periodic function with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, second means for comparing a linearly varying periodic function with said error signal to generate a second series of pulses each having a width related to the magnitude of said error signal, phase selection circuit means for combining each of said series of pulses with a periodically varying function to produce a first and second energizing signal, the phase relationship of said first and second energizing signals controlling the phase energization of said load, and switching means actuated by said energizing signals to connect the DC power source to the load to produce an effective alternating current excitation thereof.
Claim 3
Dependent Claim
37 words
A system for controlling the energization of an alternating current load from a DC source in accordance with an error signal as set forth in claim 1 wherein said linearly varying periodic function is a triangular wave.
Claim 4
Dependent Claim
38 words
A system for controlling the energization of an alternating current load from a DC source in accordance with an error signal as set forth in claim 1 wherein said periodically varying function is a square wave logic signal.
Claim 5
Dependent Claim
43 words
A system for controlling the energization of an alternating current motor from a DC source in accordance with an error signal as set forth in claim 1 wherein said first and second energizing signals are separate digital pulse trains displaced electrically 180* .
Claim 6
Independent Claim
169 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal comprising: means for comparing a triangular shaped wave function with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, means for inverting the triangular shaped wave function to generate the inverse thereof, means for comparing the inverted triangular shaped wave function with said error signal to generate a second series of pulses each having a width related to the magnitude of said error signal, phase selection circuit means for combining each of said series of pulses with a periodically varying function to produce a first and second motor phase energizing signal, the phase relationship of said first and second motor energizing signals controlling the phase energization and rotational direction of said motor, and switching means actuated by said motor energizing signals to connect the DC source to the motor winding to produce an effective alternating current excitation thereof.
Claim 7
Independent Claim
169 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal comprising: means for comparing a triangular shaped wave function with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, means for inverting the triangular shaped wave function to generate the inverse thereof, means for comparing the inverted triangular shaped wave function with said error signal to generate a second series of pulses each having a width related to the magnitude of said error signal, phase selection circuit means for combining each of said series of pulses with a periodically varying function to produce a first and second motor phase energizing signal, the phase relationship of said first and second motor energizing signals controlling the phase energization and rotational direction of said motor, and switching means actuated by said motor energizing signals to connect the DC source to the motor winding to produce an effective alternating current excitation thereof.
Claim 8
Dependent Claim
51 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 5 wherein said means for combining each of said series of pulses with a periodically varying function includes means for inverting said function to generate the inverse thereof.
Claim 9
Dependent Claim
108 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 6 wherein said means for combining further includes logic components for producing the first motor energizing signal in accordance with the equation: PSC SQW.M1 + SQW.M2 and additional logic components to produce the second motor energizing signal in accordance with the equation: NSC SQW.M2 + SQW.M1 where PSC the first motor energizing signal, SQW the periodically varying function, M1 the first series of pulses, SQW the inverse of the periodically varying function, M2 the second series of pulses, and NSC the second motor energizing signal.
Claim 10
Dependent Claim
32 words
A system for controlling an alternating motor from a DC source in accordance with an error signal as set forth in claim 7 wherein said periodically varying function is a square wave.
Claim 11
Independent Claim
168 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal comprising: means for comparing a triangular shaped wave function with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, means for inverting said error signal to generate the inverse thereof, means for comparing the inverted error signal with a triangular shaped wave function to generate a second series of pluses each having a width related to the magnitude of said error signal, phase selection circuit means for combining each of said series of pulses with a periodically varying function to produce a first and second motor phase energizing signal, the phase relationship of said first and second motor energizing signals controlling the phase energization and rotational direction of said motor, and switching means actuated by said motor energizing signals to connect the DC power source to the motor windings to produce an effective alternating current excitation thereof.
Claim 12
Independent Claim
168 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal comprising: means for comparing a triangular shaped wave function with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, means for inverting said error signal to generate the inverse thereof, means for comparing the inverted error signal with a triangular shaped wave function to generate a second series of pluses each having a width related to the magnitude of said error signal, phase selection circuit means for combining each of said series of pulses with a periodically varying function to produce a first and second motor phase energizing signal, the phase relationship of said first and second motor energizing signals controlling the phase energization and rotational direction of said motor, and switching means actuated by said motor energizing signals to connect the DC power source to the motor windings to produce an effective alternating current excitation thereof.
Claim 13
Dependent Claim
37 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 9 including means for inverting said periodically varying function to produce the inverse thereof.
Claim 14
Dependent Claim
108 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 10 wherein said means for combining further includes logic components for producing the first motor energizing signal in accordance with the equation: PSC SQW.N1 + SQW.N2 and additional logic components to produce the second motor energizing signal in accordance with the equation: NSC SQW.N2 + SQW.N1 where PSC the first motor energizing signal, SQW the periodically varying function, N1 the first series of pulses, SQW the inverse of the periodically varying function, N2 the second series of pulses, and NSC the second motor energizing signal.
Claim 15
Dependent Claim
33 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 11 wherein said periodically varying function is a square wave.
Claim 16
Dependent Claim
37 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 9 wherein said first and second motor energizing signals are displaced electrically 180* .
Claim 17
Independent Claim
187 words
A system for controlling an alternating current motor from a source of direct current in accordance with an error signal comprising: means for comparing a triangular shaped wave function varying plus and minus of zero with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, means for inverting said error signal to generate the inverse thereof, means for comparing the triangular function with the inverted error signal to generate a second series of pulses each having a width related to the magnitude of said error signal, means for combining said first and second series of pulses to produce a first and second intermediate series of pulses, means for combining each of said series of intermediate pulses with a periodically varying function to produce a first and second motor energizing signal, the phase relationship of said first and second motor energizing signals controlling the rotational direction of said motor, and switching means actuated by said motor energizing signals to connect the DC power source to the motor windings to produce an effective alternating excitation thereof.
Claim 18
Independent Claim
187 words
A system for controlling an alternating current motor from a source of direct current in accordance with an error signal comprising: means for comparing a triangular shaped wave function varying plus and minus of zero with said error signal to generate a first series of pulses each having a width related to the magnitude of said error signal, means for inverting said error signal to generate the inverse thereof, means for comparing the triangular function with the inverted error signal to generate a second series of pulses each having a width related to the magnitude of said error signal, means for combining said first and second series of pulses to produce a first and second intermediate series of pulses, means for combining each of said series of intermediate pulses with a periodically varying function to produce a first and second motor energizing signal, the phase relationship of said first and second motor energizing signals controlling the rotational direction of said motor, and switching means actuated by said motor energizing signals to connect the DC power source to the motor windings to produce an effective alternating excitation thereof.
Claim 19
Dependent Claim
51 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 14 wherein said means for combining each of said series of pulses with a periodically varying function includes means for inverting said function to produce the inverse thereof.
Claim 20
Dependent Claim
100 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 15 including logic components to produce the first motor energizing signal in accordance with the equation: PSC SQW.(P1.P2) SQW.(P1.P2) and logic components for producing the second motor energizing signal in accordance with the equation: NSC SQW.(P1.P2) + SQW.(P1.P2) where PSC the first motor energizing signal, SQW the periodically varying function, P1 the first series of pulses, P2 the second series of pulses, SQW the inverse of the periodically varying function, and NSC the second motor energizing signal.
Claim 21
Dependent Claim
33 words
A system for controlling an alternating current motor from a DC source in accordance with an error signal as set forth in claim 16 wherein said periodically varying function is a square wave.
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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) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |