Patent US4186334A successfully refreshed from Google Patents.
US4186334A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control systems of alternating current motors
Assignee: Toshiba Corp
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Filing: 1978-02-07
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Granted: 1980-01-29
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Expires: 1998-02-07
Abstract
Abstract In a control system of an alternating current motor energized by serially connected rectifier and inverter wherein the output DC voltage of the rectifier is controlled by a phase controller which is controlled by a phase control signal and the output frequency of the inverter is controlled by a speed reference signal there is provided a power factor detector which differentiates the phase control signal or the DC voltage and the output of the phase detector is added to the speed reference signal so as to suppress low frequency oscillations of the torque of the motor.
Inventors
- 👤 Akio Hirata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:24
CPC Classifications
H; H02; H02P; H02P27/00; H02P27/04; H02P27/06; H02P23/00; H02P23/26
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
102 words
In a control system of an alternating current motor which is energized by a current type frequency converter including a serially connected rectifier and inverter wherein the output direct current voltage of said rectifier is controlled by a phase controller which is controlled by a phase control signal, the output frequency of said inverter and a speed reference signal, the improvement which comprises a power factor detector which differentiates said phase control signal, and means for adding the output of said power factor detector to said speed reference signal so as to suppress low frequency oscillations of the torque of said motor.
Claim 2
Dependent Claim
102 words
In a control system of an alternating current motor which is energized by a current type frequency converter including a serially connected rectifier and inverter wherein the output direct current voltage of said rectifier is controlled by a phase controller which is controlled by a phase control signal, the output frequency of said inverter and a speed reference signal, the improvement which comprises a power factor detector which differentiates said phase control signal, and means for adding the output of said power factor detector to said speed reference signal so as to suppress low frequency oscillations of the torque of said motor.
Claim 3
Dependent Claim
40 words
The control system according to claim 1 which further comprises a voltage/current controller which converts said speed reference signal into said phase control signal in response to the input current to said rectifier and the output voltage of said inverter.
Claim 4
Dependent Claim
106 words
In a control system of an alternating current motor which is energized by a current type frequency converter including a serially connected rectifier and inverter wherein the output direct current voltage of said rectifier is controlled by a phase controller which is controlled by a phase control signal, the output frequency of said inverter and a speed reference signal, the improvement which comprises a power factor detector which differentiates the output direct current voltage of said rectifier, and means for adding the output of said power factor detector to said speed reference signal so as to suppress low frequency oscillations of the torque of said motor.
Claim 5
Dependent Claim
106 words
In a control system of an alternating current motor which is energized by a current type frequency converter including a serially connected rectifier and inverter wherein the output direct current voltage of said rectifier is controlled by a phase controller which is controlled by a phase control signal, the output frequency of said inverter and a speed reference signal, the improvement which comprises a power factor detector which differentiates the output direct current voltage of said rectifier, and means for adding the output of said power factor detector to said speed reference signal so as to suppress low frequency oscillations of the torque of said motor.
Claim 6
Dependent Claim
40 words
The control system according to claim 3 which further comprises a voltage/current controller which converts said speed reference signal into said phase control signal in response to the input current to said rectifier and the output voltage of said inverter.
References Cited (Backward Citations)
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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) | 1983-01-28 | 1983-07-30 | 1984-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-28 | 1987-07-30 | 1988-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-28 | 1991-07-30 | 1992-01-29 | $7700.00 | Window Closed / Lapsed |