US3947737A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gate control of thyristor converters for reversibly driving a D.C. electric motor
Assignee: Toshiba Corp
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Filing: 1974-05-30
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Granted: 1976-03-30
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Expires: 1994-05-30
Abstract
Abstract A gate control for thyristor converters connected in opposition to reversibly drive a D.C. electric motor in which one of the thyristor converters operates as a rectifier and the other remains still when the motor runs forward, and vice versa. The gate control includes an operational amplifier to carry out current control for the converters and to generate an output therefrom which follows the motor armature voltage during the switchover between converters to prepare for reverse rotation of the motor. The other converter, which operates momentarily as an inverter to feed electric energy from the motor back to an A.C. electric voltage supply thereof to reduce the motor speed, is controlled to enable its inverter voltage to coincide substantially with the motor armature voltage so as not to cause excessive rushing current from the motor into the inverter at the instant of the switchover.
Inventors
- 👤 Takashi Kimura
- 👤 Toshiyuki Ogita
- 👤 Takahiro Sumihana
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:56
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/03; H02P7/05
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
340 words
A gate control for reversibly driving a D.C. electric motor comprising: a first thyristor converter for operating as a rectifier for energizing the motor to drive it forward; a second thyristor converter for remaining still during the time the motor runs in the forward direction; means for energizing the motor from the first thyristor converter and then from the second thyristor converter; means for connecting an A.C. voltage supply to the converters; means for generating gating pulses synchronized with the frequencies of the A.C. voltage supply for the converters; first and second gating circuits for selectively applying the gating pulses from the gating pulse generating means to gate electrodes of the converters; means for comparing a voltage signal corresponding to the rotational speed signal of the motor with a speed reference voltage signal and for feeding a speed deviation voltage signal to the pulse generating means to phase shift the gating pulses to enable adjustment of the output voltage from the converter operating as a rectifier to adjust the motor speed to coincide substantially with the reference speed indicated by the speed reference voltage signal; operational amplifier means having an integrating function for effecting current control of the converters in response to the deviation current signal by comparing the converter current with the deviation derived from the speed deviation feeding means to render the converter current substantially equal to the amplitude of the speed deviation; and means for dinconnecting the operational amplifier means from the speed deviation feeding means and for alternately applying an electrical voltage signal responsive to the motor speed and a modified feedback signal from the output terminal of the operational amplifier to an input terminal of the operational amplifier during the time the converters are switched from one state to another to prepare for reverse rotation of the motor so that the phase adjustment of the gating pulses emanating from the gate control follows the electrical signal voltage responsive to the motor speed during the time the thyristor converters are switched from one state to another.
Claim 2
Dependent Claim
340 words
A gate control for reversibly driving a D.C. electric motor comprising: a first thyristor converter for operating as a rectifier for energizing the motor to drive it forward; a second thyristor converter for remaining still during the time the motor runs in the forward direction; means for energizing the motor from the first thyristor converter and then from the second thyristor converter; means for connecting an A.C. voltage supply to the converters; means for generating gating pulses synchronized with the frequencies of the A.C. voltage supply for the converters; first and second gating circuits for selectively applying the gating pulses from the gating pulse generating means to gate electrodes of the converters; means for comparing a voltage signal corresponding to the rotational speed signal of the motor with a speed reference voltage signal and for feeding a speed deviation voltage signal to the pulse generating means to phase shift the gating pulses to enable adjustment of the output voltage from the converter operating as a rectifier to adjust the motor speed to coincide substantially with the reference speed indicated by the speed reference voltage signal; operational amplifier means having an integrating function for effecting current control of the converters in response to the deviation current signal by comparing the converter current with the deviation derived from the speed deviation feeding means to render the converter current substantially equal to the amplitude of the speed deviation; and means for dinconnecting the operational amplifier means from the speed deviation feeding means and for alternately applying an electrical voltage signal responsive to the motor speed and a modified feedback signal from the output terminal of the operational amplifier to an input terminal of the operational amplifier during the time the converters are switched from one state to another to prepare for reverse rotation of the motor so that the phase adjustment of the gating pulses emanating from the gate control follows the electrical signal voltage responsive to the motor speed during the time the thyristor converters are switched from one state to another.
Claim 3
Dependent Claim
64 words
A gate control according to claim 1 wherein the gating circuits for applying the gating pulses to the gate electrodes of the converters comprise a first AND gate for introducing the gating pulses to one of the converters and a second AND gate for introducing the gating pulses to the other of the converters without the first and second AND gates being simultaneously on.
Claim 4
Dependent Claim
86 words
A gate control according to claim 1 wherein: the operational amplifier means comprises an operational amplifier for controlling the current flowing between the converters; the electric motor has an input terminal and a static switch connected in series therewith for feeding the armature voltage of the motor back to the input terminal of the operational amplifier, and the static switch is closed only during the preparatory period of switching the converters from one state to another when a reversible running command is coupled to the motor.
Claim 5
Dependent Claim
99 words
A gate control according to claim 1 wherein the operational amplifier disconnect means comprises logic means which responds to the switching command signal for switching the converters from one state to another for responding to the zero current signal from the main circuit of the converters and which responds to the running command signal from a master control means so that the logic circuit means enables the gate control to prepare for switching the converters from one state to another and enables the converter about to change from one state to another to prepare for the momentary inverter operation.
Claim 6
Dependent Claim
212 words
A gate control means according to claim 4 wherein: the logic means comprises first, second and third operational amplifiers connected in tandem and a fourth operational amplifier, the first operation amplifier being for the speed control of the motor, the second operational amplifier being for the current control of the converters and the third operational amplifier being for the voltage control of the converters, the logic means further comprises a power amplifier to amplify the resultant output signal obtained from the first, second and third operational amplifiers, the output terminal of the third operational amplifier being connected to the input terminal of the power amplifier through a first resistor, the fourth operational amplifier being connected between the output terminal of the third operational amplifier and a summing point located at the input terminal of the power amplifier through a normally open static switch and a second resistor connected in series therewith, a first circuit comprising the third and fourth operational amplifiers, the static switch and the second resistor having a gain which is substantially twice that of a second circuit which comprises the third operational amplifier and the first resistor so that the first circuit switches the converters from one state to another by closing the static contact for reverse motor running.
Claim 7
Dependent Claim
65 words
A gate control according to claim 5 wherein the logic means comprises an output terminal for generating a signal to override the gate control signal generated by the pre-stage operational amplifiers, and the override signal is applied to the power amplifier when preparation is made for the switching of the converters from one state to another in preparation for the reverse running the of motor.
Claim 8
Dependent Claim
52 words
A gate control according to claim 4 wherein the logic means further comprises output terminals which generate signals for switching the AND gates connected to corresponding converters, and the signals are fed alternately and selectively to the AND gates in response to the switching of the converters from one state to another.
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) | 1979-03-30 | 1979-09-29 | 1980-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-30 | 1983-09-29 | 1984-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-30 | 1987-09-29 | 1988-03-30 | $7700.00 | Window Closed / Lapsed |