US3908130A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Starter-generator utilizing phase controlled rectifiers to drive a dynamoelectric machine as a brushless motor in the starting mode to increase the torque output of the machine through phase angle control by reducing the machine counter EMF
Assignee: General Electric Co
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Filing: 1974-08-30
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Granted: 1975-09-23
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Expires: 1994-08-30
Abstract
Abstract The instant invention is an improvement of a starter-generator arrangement in which a dynamoelectric machine is driven as a brushless DC motor to start a dynamic load such as a jet engine and as a synchronous constant frequency generator after the jet engine is ignited and brought up to speed. A plurality of cycloconverters utilizing phase controlled rectifier banks are operated from a constant frequency supply source to supply current to the armature windings of the machine in the starting mode. Position sensing elements such as Hall generators sense the rotor position relative to the machine windings and generate enabling signals to control conduction of the phase controlled rectifiers to supply current to the proper armature windings so that the machine functions essentially as a DC brushless motor. The stator current conduction angle with respect to rotor position is varied as a function of speed to vary the phase angle of advance and provide for commutation of the SCR''s by the machine voltage at higher speeds. In addition, at machine speeds where the counter EMF generated in the armature windings rises sufficiently to reduce armature current, means are provided for reducing the counter EMF by further advancing the phase angle and providing additional torque to accelerate the engine. Specifically, a control signal proportional to the armature current is utilized to increase the phase angle between the armature current, the flux, and the machine voltage sufficiently to reduce the machine counter EMF thereby increasing the armature current and providing additional accelerating torque over an extended speed range to the jet engine.
Inventors
- 👤 David Logan Lafuze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:14
CPC Classifications
H; H02; H02P; H02P1/00; H02P1/16; H02P1/46; H02P1/52; F; F02; F02N; F02N11/00; F02N11/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
339 words
In a starter-generator system the combination of: a. A dynamoelectric machine for operation both as a brushless DC motor and as a constant frequency AC generator, b. Cycloconverter means coupled to said machine for selectively supply current to the machine armature windings during motoring operation and for converting the frequency of the output from the machine to provide a constant frequency output from the machine during generator operation, said cycloconverter means including banks of oppositely poled, phase controlled, gated switching devices, c. Means to operate said dynamoelectric machine as a brushless DC motor including: 1. a source of fixed frequency alternating supply voltage coupled to said banks of switching devices, 2. means for sensing the rotor position of said dynamoelectric machine and for producing enabling signals for gating selected ones for said switching devices in sequence to permit current flow in selected armature windings as a function of rotor position so that current flow is in the armature winding having high flux associated therewith to produce positive torque, 3. means responsive to armature current level in said machine for shiftint the phase of the enabling signals to vary the firing angle of the switchiNg devices over a speed range wherein the machine counter EMF is high and reduces armature current to reduce the counter EMF sufficiently to increase the current to allow the machine to produce accelerating torque in said speed range. d. A source of constant frequency reference waves, e. means for converting the system from the motoring to the generating mode including, 1. means responsive to the speed of the dynamoelectric machine for disconnecting the supply voltage and the rotor position gating means from the banks of switching devices of said cycloconverters when the machine reaches a speed at which it is to operate as a generator, and means responsive to the speed of the dynamoelectric machine for coupling said source of constant frequency reference waves to said switching devices to convert the machine voltage of varying frequency to a constant frequency output in the generating mode.
Claim 2
Dependent Claim
339 words
In a starter-generator system the combination of: a. A dynamoelectric machine for operation both as a brushless DC motor and as a constant frequency AC generator, b. Cycloconverter means coupled to said machine for selectively supply current to the machine armature windings during motoring operation and for converting the frequency of the output from the machine to provide a constant frequency output from the machine during generator operation, said cycloconverter means including banks of oppositely poled, phase controlled, gated switching devices, c. Means to operate said dynamoelectric machine as a brushless DC motor including: 1. a source of fixed frequency alternating supply voltage coupled to said banks of switching devices, 2. means for sensing the rotor position of said dynamoelectric machine and for producing enabling signals for gating selected ones for said switching devices in sequence to permit current flow in selected armature windings as a function of rotor position so that current flow is in the armature winding having high flux associated therewith to produce positive torque, 3. means responsive to armature current level in said machine for shiftint the phase of the enabling signals to vary the firing angle of the switchiNg devices over a speed range wherein the machine counter EMF is high and reduces armature current to reduce the counter EMF sufficiently to increase the current to allow the machine to produce accelerating torque in said speed range. d. A source of constant frequency reference waves, e. means for converting the system from the motoring to the generating mode including, 1. means responsive to the speed of the dynamoelectric machine for disconnecting the supply voltage and the rotor position gating means from the banks of switching devices of said cycloconverters when the machine reaches a speed at which it is to operate as a generator, and means responsive to the speed of the dynamoelectric machine for coupling said source of constant frequency reference waves to said switching devices to convert the machine voltage of varying frequency to a constant frequency output in the generating mode.
Claim 3
Dependent Claim
57 words
means for sensing the rotor position of said dynamoelectric machine and for producing enabling signals for gating selected ones for said switching devices in sequence to permit current flow in selected armature windings as a function of rotor position so that current flow is in the armature winding having high flux associated therewith to produce positive torque,
Claim 4
Dependent Claim
57 words
means for sensing the rotor position of said dynamoelectric machine and for producing enabling signals for gating selected ones for said switching devices in sequence to permit current flow in selected armature windings as a function of rotor position so that current flow is in the armature winding having high flux associated therewith to produce positive torque,
Claim 5
Dependent Claim
147 words
The starter-generator system according to claim 1 wherein said rotor position gating means includes means for sensing said rotor pole position and for producing a polyphase signal proportional to the pole flux, means for comparing said polyphase signals and means for producing a gating signal when the pole flux adjacent a given armature winding is high but the flux adjacent to the next armature winding phase is low, and means responsive to armature current level for producing a control signal when the armature current drops below a given level at speeds when the counter EMF of the machine is too high and means responsive to said control signal to vary the phase of said gating signal so that the firing angle of said switching devices is advanced thereby advancing the phase angle between the armature current and the flux to reduce the counter MEF of the machine.
Claim 6
Dependent Claim
68 words
The starter-generator system according to claim 2 wherein said means for producing a gating signal includes switching amplifier means for converting said polyphase signals to substantially rectangular signals, and means responsive to said armature current for varying the switching point of said amplifiers as a function of the armature current to vary thereby the phases of said enabling signal and hence the triggering angle of said switching devices.
Claim 7
Dependent Claim
85 words
means responsive to armature current level in said machine for shiftint the phase of the enabling signals to vary the firing angle of the switchiNg devices over a speed range wherein the machine counter EMF is high and reduces armature current to reduce the counter EMF sufficiently to increase the current to allow the machine to produce accelerating torque in said speed range. d. A source of constant frequency reference waves, e. means for converting the system from the motoring to the generating mode including,
Claim 8
Dependent Claim
85 words
means responsive to armature current level in said machine for shiftint the phase of the enabling signals to vary the firing angle of the switchiNg devices over a speed range wherein the machine counter EMF is high and reduces armature current to reduce the counter EMF sufficiently to increase the current to allow the machine to produce accelerating torque in said speed range. d. A source of constant frequency reference waves, e. means for converting the system from the motoring to the generating mode including,
Claim 9
Dependent Claim
117 words
The starter-generator system according to claim 1 wherein said means for varying the phase angle of said gating signals includes a speed responsive means for varying the phase over a first range of speed wherein said machine voltage frequency is equal to or greater than one-half of said supply frequency to permit commutation of the switching devices over said first range by the machine voltage, and to vary the phase further over another, greater range of speeds in response to armature current level to advance the phase of said signal further to reduce the counter EMF of the machine over said further speed range to provide continued torque output from said machine over said further speed range.
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) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |