US3577052A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ac motor control system with synchronous speed change
Assignee: Individual
•
Filing: 1968-10-17
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Granted: 1971-05-04
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Expires: 1988-10-17
Abstract
Abstract A variable DC power source supplies a DC voltage to a static inverter which provides a three-phase alternating voltage output to drive an AC motor. A ring counter which is cycled by a voltage controlled oscillator generates three-phase timing signals to control the frequency of the inverter output. An input control signal is coupled to the voltage controlled oscillator through a rate control means. The rate control means generates a voltage output to the voltage controlled oscillator which is proportional to the input control signal and follows and adjustment of the input control signal from one level to another at a predetermined rate. The output generated by the rate control means also controls the magnitude of the DC voltage output of the DC power source. An adjustment of the input control signal results in a proportional change in the magnitude and the frequency of the inverter output.
Inventors
- 👤 David Elvis Bauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:55
CPC Classifications
H; H02; H02P; H02P23/00; H02P23/24; H02P27/00; H02P27/04; H02P27/047
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
253 words
A system for generating a three-phase alternating output to an AC motor, said three-phase alternating output having a magnitude and a frequency which are proportionally adjustable in response to a change in the magnitude of a speed adjustment input signal to control the speed and the torque of said AC motor, said system comprising: an adjustable direct voltage generating means for generating a direct voltage output proportional to the magnitude of said speed adjustment signal; a static inverter supplied by said direct voltage for generating a three-phase alternating output having a magnitude proportional to the magnitude of said direCt voltage and an adjustable frequency; a rate control means having said speed adjustment signal as an input for generating a rate control signal having a magnitude which is a function of the magnitude of said speed adjustment signal, said rate control means including means for generating a signal of predetermined waveform so that the maximum time rate of change of said rate control signal is limited to said predetermined waveform regardless of the time rate of change of said speed adjustment input signal, said rate control signal being coupled to said direct voltage generating means for controlling the magnitude of said direct voltage output; and a timing signal generating means supplied by said rate control signal for generating three-phase timing signals having a frequency proportional to the magnitude of said rate control signal, said three-phase timing signals being coupled to said static inverter to control the frequency of said static inverter three-phase alternating output.
Claim 2
Independent Claim
253 words
A system for generating a three-phase alternating output to an AC motor, said three-phase alternating output having a magnitude and a frequency which are proportionally adjustable in response to a change in the magnitude of a speed adjustment input signal to control the speed and the torque of said AC motor, said system comprising: an adjustable direct voltage generating means for generating a direct voltage output proportional to the magnitude of said speed adjustment signal; a static inverter supplied by said direct voltage for generating a three-phase alternating output having a magnitude proportional to the magnitude of said direCt voltage and an adjustable frequency; a rate control means having said speed adjustment signal as an input for generating a rate control signal having a magnitude which is a function of the magnitude of said speed adjustment signal, said rate control means including means for generating a signal of predetermined waveform so that the maximum time rate of change of said rate control signal is limited to said predetermined waveform regardless of the time rate of change of said speed adjustment input signal, said rate control signal being coupled to said direct voltage generating means for controlling the magnitude of said direct voltage output; and a timing signal generating means supplied by said rate control signal for generating three-phase timing signals having a frequency proportional to the magnitude of said rate control signal, said three-phase timing signals being coupled to said static inverter to control the frequency of said static inverter three-phase alternating output.
Claim 3
Dependent Claim
38 words
The apparatus as described in claim 1 further including means responsive to the output current from said static inverter to said motor for disabling said direct voltage generating means if said output current is not within predetermined limits.
Claim 4
Dependent Claim
25 words
The apparatus as described in claim 2 wherein said direct voltage generating means limits the current supplied to said static inverter to a predetermined value.
Claim 5
Dependent Claim
87 words
The apparatus as described in claim 3 further including means responsive to a direction control input signal having two states and to said rate control signal for (i) clamping said speed adjustment input signal to ground potential when said direction control input signal changes state, (ii) releasing said clamp on said speed adjustment input signal when said rate control signal has been reduced to ground potential, and, (iii) reversing the phase rotation of said timing signals when said rate control signal has been reduced to ground potential.
Claim 6
Dependent Claim
59 words
The apparatus as described in claim 4 wherein said direct voltage generating means includes means for generating a substantially square wave voltage wave shape output having an adjustable magnitude, said voltage wave shape being independent of the magnitude of said voltage wave shape and a rectifying and filtering means for converting said square wave to said direct voltage output.
Claim 7
Dependent Claim
106 words
The apparatus as described in claim 5 wherein said square wave voltage wave shape generating means comprises a transformer having an alternating voltage input, said transformer having an EI core, a primary winding having said alternating voltage applied and a secondary winding both said windings wound on said center leg of said core, said core being divided into a first magnetic section and a second magnetic section by magnetic shunts disposed between said center leg and said outside legs separating said primary and said secondary windings, a capacitor coupled across said secondary winding for maintaining the flux in said second section of said core near saturation.
Claim 8
Dependent Claim
45 words
The apparatus as described in claim 6 wherein said transformer further includes two control windings wound on said outside legs in said second section and connected in series opposition a control current passing through said control windings reducing the voltage appearing in said secondary winding.
Claim 9
Dependent Claim
63 words
The apparatus as described in claim 7 further including transformer control means responsive to the magnitude of said rate control signal and to the magnitude of said static inverter three-phase alternating output for controlling said control current flowing through said control windings on said transformer to maintain said direct voltage generated by said direct voltage generating means proportional to said rate control signal.
Claim 10
Dependent Claim
42 words
The apparatus as described in claim 8 wherein said timing signal generating means comprises a voltage controlled oscillator having said rate control signal applied and generating a periodic output signal having a frequEncy proportional to the magnitude of said rate control signal.
Claim 11
Dependent Claim
58 words
The apparatus as described in claim 9 wherein said timing signal generating means further includes a ring counter having said periodic signal as an input and generating said three-phase timing signals as an output, said three-phase timing signals having a frequency proportional to the frequency of said periodic signal, each phase of said timing signals comprising complementary signals.
Claim 12
Dependent Claim
423 words
The apparatus as described in claim 10 wherein said static inverter comprises: three pairs of switching silicon controlled rectifiers each of said pairs having a particular phase of said three-phase timing signals applied thereto and including a first and a second switching silicon controlled rectifier, said first switching silicon controlled rectifier in each of said pairs having its anode electrode coupled to said direct voltage input to said static inverter and its cathode electrode coupled to the anode electrode of said second switching silicon controlled rectifier, the cathode electrode of said second silicon controlled rectifier being coupled to ground, a signal appearing at a phase output point intermediate the cathode electrode of said first switching silicon controlled rectifier and the anode electrode of said second switching silicon controlled rectifier being one phase of said three-phase output of said static inverter, the anode electrode of each of said switching silicon controlled rectifiers in each of said pairs being coupled to the anode electrode of an associated commutation silicon controlled rectifier, the cathode electrode of said commutation silicon controlled rectifier being series connected with a commutation capacitor to the cathode electrode of said switching silicon controlled rectifier; first means for applying a gate signal to the gate electrode of each of said switching silicon controlled rectifiers on alternative half cycles of said particular phase of said timing signals, said gate signal being positive with respect to the cathode electrode of said switching silicon controlled rectifier, said switching silicon controlled rectifiers in each of said pairs becoming alternately conductive during one cycle of said particular phase of said timing signals; second means for applying a potential to the cathode electrode of said commutation silicon controlled rectifier, said potential being negative with respect to the potential at the anode electrode of said switching silicon controlled rectifier, said negative potential charging said commutation capacitor on alternate half cycles of said particular phase of said timing signals substantially simultaneous with the application of said gate signal to said gate electrode of said switching controlled rectifier; third means for applying a second gate signal to the gate electrode of said commutation silicon controlled rectifiers, said second gate signal being positive with respect to the cathode electrode of said commutation silicon controlled rectifier and occuring on alternate half cycles of said particular phase of said timing signals, said alternate half cycles being 180* out of phase with said alternate half cycles of said timing signals during which said gate signal is applied to the gate electrode said switching silicon controlled rectifier.
Claim 13
Dependent Claim
38 words
The apparatus as described in claim 11 wherein said first means further includes means for delaying the application of said gate signal to said gate electrode of said switching silicon controlled rectifier for a predetermined period of time.
Claim 14
Dependent Claim
21 words
The apparatus as described in claim 12 further including a first inductor connected in parallel with said commutation silicon controlled rectifier.
Claim 15
Dependent Claim
49 words
The apparatus as described in claim 13 further including a second inductance coupled intermediate the cathode electrode of said first silicon controlled rectifier and said phase output point and a third inductance coupled between said phase output point and the anode electroDe of said second switching silicon controlled rectifier.
Claim 16
Dependent Claim
87 words
The apparatus as described in claim 1 further including means responsive to a direction control input signal having two states and to said rate control signal for (i) clamping said speed adjustment input signal to ground potential when said direction control input signal changes state, (ii) releasing said clamp on said speed adjustment input signal when said rate control signal has been reduced to ground potential, and (iii) reversing the phase rotation of said timing signals when said rate control signal has been reduced to ground potential.
Claim 17
Independent Claim
613 words
A system for generating a three-phase alternating output to an AC motor, said three-phase alternating output having a magnitude and a frequency which are proportionally adjustable in response to a change in the magnitude of a speed adjustment input signal to control the speed and the torque of said AC motor, said system comprising: an adjustable direct voltage generating means for generating a direct voltage output proportional to the magnitude of said speed adjustment signal; a rate control means having said speed adjustment signal as an input for generating a rate control signal output having a magnitude proportional to the magnitude of said speed adjustment signal and for changing the magnitude of said rate control signal at a predetermined rate in response to a change in the magnitude of said speed adjustment level, said rate control signal being coupled to said direct voltage generating means for controlling the magnitude of said direct voltage output; a timing signal generating means supplied by said rate control signal for generating three-phase timing signals having a frequency proportional to the magnitude of said rate control signal; and a static inverter having said direct voltage and said three-phase timing signals applied for generating said three-phase alternating output including, three pairs of switching silicon controlled rectifiers each of said pairs having a particular phase of said three-phase timing signals applied thereto and including a first and a second switching silicon controlled rectifier, said first switching silicon controlled rectifier in each of said pairs having its anode electrode coupled to said direct voltage input to said static inverter and its cathode electrode coupled to the anode electrode of said second switching silicon controlled rectifier, the of said second silicon controlled rectifier being coupled to ground, a signal appearing at a phase output point intermediate the cathode electrode of said first switching silicon controlled rectifier and the anode electrode of said second switching silicon controlled rectifier being one phase of said three-phase output of said static inverter, the anode electrode of each of said switching silicon controlled rectifiers in each of said pairs being coupled to the anode electrode of an associated commutation silicon controlled rectifier, the cathode electrode of said commutation silicon controlled rectifier being series connected with a commutation capacitor to the cathode electrode of said switching silicon controlled rectifier, first means for applying a gate signal to the gate electrode of each of said switching silicon controlled rectifiers on alternative half cycles of said particular phase of said timing signals, said gate signal being positive with respect to the cathode electrode of said switching silicon controlled rectifier, said switching silicon controlled rectifiers in each of said pairs becoming alternately conductive during one cycle of said particular phase of said timing signals, second means for applying a potential to the cathode electrode of said commutation silicon controlled rectifier, said potential being negative with respect to the potential at the anode electrode of said switching silicon controlled rectifier, said negative potential charging said commutation capacitor on alternate half cycles of said particular phase of sAid timing signals substantially simultaneous with the application of said gate signal to said gate electrode of said switching silicon controlled rectifier, third means for applying a second gate signal to the gate electrode of said commutation silicon controlled rectifiers, said second gate signal being positive with respect to the cathode electrode of said commutation silicon controlled rectifier and occuring on alternate half cycles of said particular phase of said timing signals, said alternate half cycles being 180* out of phase with said alternate half cycles of said timing signals during which said gate signal is applied to the gate electrode said switching silicon controlled rectifier.
Claim 18
Independent Claim
613 words
A system for generating a three-phase alternating output to an AC motor, said three-phase alternating output having a magnitude and a frequency which are proportionally adjustable in response to a change in the magnitude of a speed adjustment input signal to control the speed and the torque of said AC motor, said system comprising: an adjustable direct voltage generating means for generating a direct voltage output proportional to the magnitude of said speed adjustment signal; a rate control means having said speed adjustment signal as an input for generating a rate control signal output having a magnitude proportional to the magnitude of said speed adjustment signal and for changing the magnitude of said rate control signal at a predetermined rate in response to a change in the magnitude of said speed adjustment level, said rate control signal being coupled to said direct voltage generating means for controlling the magnitude of said direct voltage output; a timing signal generating means supplied by said rate control signal for generating three-phase timing signals having a frequency proportional to the magnitude of said rate control signal; and a static inverter having said direct voltage and said three-phase timing signals applied for generating said three-phase alternating output including, three pairs of switching silicon controlled rectifiers each of said pairs having a particular phase of said three-phase timing signals applied thereto and including a first and a second switching silicon controlled rectifier, said first switching silicon controlled rectifier in each of said pairs having its anode electrode coupled to said direct voltage input to said static inverter and its cathode electrode coupled to the anode electrode of said second switching silicon controlled rectifier, the of said second silicon controlled rectifier being coupled to ground, a signal appearing at a phase output point intermediate the cathode electrode of said first switching silicon controlled rectifier and the anode electrode of said second switching silicon controlled rectifier being one phase of said three-phase output of said static inverter, the anode electrode of each of said switching silicon controlled rectifiers in each of said pairs being coupled to the anode electrode of an associated commutation silicon controlled rectifier, the cathode electrode of said commutation silicon controlled rectifier being series connected with a commutation capacitor to the cathode electrode of said switching silicon controlled rectifier, first means for applying a gate signal to the gate electrode of each of said switching silicon controlled rectifiers on alternative half cycles of said particular phase of said timing signals, said gate signal being positive with respect to the cathode electrode of said switching silicon controlled rectifier, said switching silicon controlled rectifiers in each of said pairs becoming alternately conductive during one cycle of said particular phase of said timing signals, second means for applying a potential to the cathode electrode of said commutation silicon controlled rectifier, said potential being negative with respect to the potential at the anode electrode of said switching silicon controlled rectifier, said negative potential charging said commutation capacitor on alternate half cycles of said particular phase of sAid timing signals substantially simultaneous with the application of said gate signal to said gate electrode of said switching silicon controlled rectifier, third means for applying a second gate signal to the gate electrode of said commutation silicon controlled rectifiers, said second gate signal being positive with respect to the cathode electrode of said commutation silicon controlled rectifier and occuring on alternate half cycles of said particular phase of said timing signals, said alternate half cycles being 180* out of phase with said alternate half cycles of said timing signals during which said gate signal is applied to the gate electrode said switching silicon controlled rectifier.
Claim 19
Dependent Claim
38 words
The apparatus as described in claim 16 wherein said first means further includes means for delaying the application of said gate signal to said gate electrode of said switching silicon controlled rectifier for a predetermined period of time.
Claim 20
Dependent Claim
21 words
The apparatus as described in claim 17 further including a first inductor connected in parallel with said commutation silicon controlled rectifier.
Claim 21
Dependent Claim
49 words
The apparatus as described in claim 18 further including a second inductance coupled intermediate the cathode electrode of said first silicon controlled rectifier and said phase output point and a third inductance coupled between said phase output point and the anode electrode of said second switching silicon controlled rectifier.
Claim 22
Dependent Claim
38 words
The apparatus as described in claim 19 further including means responsive to the output current from said static inverter to said motor for disabling said direct voltage generating means if said output current is not within predetermined limits.
Claim 23
Dependent Claim
25 words
The apparatus as described in claim 20 wherein said direct voltage generating means limits the current supplied to said static inverter to a predetermined value.
Claim 24
Dependent Claim
87 words
The apparatus as described in claim 21 further including means responsive to a direction control input signal having two states and to said rate control signal for (i) clamping said speed adjustment input signal to ground potential when said direction control input signal changes state, (ii) releasing said clamp on said speed adjustment input signal when said rate control signal has been reduced to ground potential, and, (iii) reversing the phase rotation of said timing signals when said rate control signal has been reduced to ground potential.
Claim 25
Dependent Claim
56 words
The apparatus as described in claim 22 wherein said direct voltage generating means includes means for generating a substantially square wave voltage waveshape output having an adjustable magnitude, said voltage waveshape being independent of the magnitude of said voltage waveshape and a rectifying and filtering means for converting said square wave to said direct voltage output.
Claim 26
Dependent Claim
105 words
The apparatus as described in claim 23 wherein said square wave voltage waveshape generating means comprises a transformer having an alternating voltage input, said transformer having an EI core, a primary winding having said alternating voltage applied and a secondary winding both said windings wound on said center leg of said core, said core being divided into a first magnetic section and a second magnetic section by magnetic shunts disposed between said center leg and said outside leg separating said primary and said secondary windings, a capacitor coupled across said secondary winding for maintaining the flux in said second section of said core near saturation.
Claim 27
Dependent Claim
45 words
The apparatus as described in claim 24 wherein said transformer further includes two control windings wound on said outside legs in said second section and connected in series opposition a control current passing through said control windings reducing the voltage appearing in said secondary winding.
Claim 28
Dependent Claim
63 words
The apparatus as described in claim 23 further including transformer control means responsive to the magnitude of said rate control signal and to the magnitude of said static inverter three-phase alternaTing output for controlling said control current flowing through said control windings on said transformer to maintain said direct voltage generated by said direct voltage generating means proportional to said rate control signal.
Claim 29
Dependent Claim
42 words
The apparatus as described in claim 26 wherein said timing signal generating means comprises a voltage controlled oscillator having said rate control signal applied and generating a periodic output signal having a frequency proportional to the magnitude of said rate control signal.
Claim 30
Dependent Claim
58 words
The apparatus as described in claim 27 wherein said timing signal generating means further includes a ring counter having said periodic signal as an input and generating said three-phase timing signals as an output, said three-phase timing signals having a frequency proportional to the frequency of said periodic signal, each phase of said timing signals comprising complementary signals.
Claim 31
Independent Claim
87 words
A system for generating an output signal for energizing an AC motor, comprising: means for generating a linear ramp signal; a static inverter for generating said output signal; means for producing a signal to control both the frequency and level of said output signal; and means for changing said control signal to control the torque and speed of said motor, said changing means being responsive to said ramp signal generating means to limit the rate at which said control signal may be changed to a predetermined maximum.
Claim 32
Independent Claim
87 words
A system for generating an output signal for energizing an AC motor, comprising: means for generating a linear ramp signal; a static inverter for generating said output signal; means for producing a signal to control both the frequency and level of said output signal; and means for changing said control signal to control the torque and speed of said motor, said changing means being responsive to said ramp signal generating means to limit the rate at which said control signal may be changed to a predetermined maximum.
Claim 33
Dependent Claim
43 words
A system as defined in claim 29 wherein said ramp signal generating means comprises: a constant current source; an energy storage device; and means for charging said energy storage device from said current source in response to a change in said control signal.
Claim 34
Dependent Claim
53 words
A system as defined in claim 29 wherein said ramp signal generating means produces a first and second ramp signal, and wherein said control signal changing means is responsive to said first ramp signal when said motor speed is increased, and responsive to said second ramp signal when said motor speed is reduced.
Claim 35
Dependent Claim
112 words
A system as defined in claim 29 additionally comprising: means for reversing motor direction comprising: means for producing a signal to initiate motor speed reversal; means responsive to said speed reversal signal and said ramp signal for reducing motor speed to zero at a predetermined rate; means for monitoring motor speed to determine when said motor speed is zero; means responsive to said motor speed monitoring means and said speed reversal signal for reversing motor direction when said motor speed is zero; and means responsive to said speed reversal signal for increasing motor speed to a predetermined level at a predetermined rate of change after operation of said motor direction reversing means.
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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) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |