US4633158A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system for an AC motor
Assignee: Toshiba Mitsubishi Electric Industrial Systems Corp
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Filing: 1984-11-01
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Granted: 1986-12-30
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Expires: 2004-11-01
Abstract
Abstract A control system for an AC motor to be driven by an inverter, wherein a control lead angle β of the AC motor drive current is controlled based on the detection of an actual overlapped angle, a set overlapped angle, a detected motor speed, a detected magnitude of the acceleration-deceleration rate of motor speed, a detected amount of current from a power source and/or a detected magnitude of the change rate in the current from the power source.
Inventors
- 👤 Akio Hirata
- 👤 Yosio Naito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:52
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/02; H02P25/022; H02P25/024
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
187 words
A control system for controlling the operation of an AC motor, comprising: converter means for converting an AC current from a power source into a DC current; phase control means for controlling said converter means; reactor means for smoothing a DC current output from said converter means; inverter means for converting the smoothed DC current output into an AC current output, said inverter means adapted to drive said AC motor by means of said AC current output; means for detecting an overlapped angle of said AC current signal supplied to said converter means; rate detector means for at least detecting the acceleration-deceleration rate of said AC motor; overlapped angle setter means for setting an overlapped angle of said inverter means to a specified value; and means for controlling a control lead angle of said inverter means in accordance with the overlapped angle set by said overlapped angle setter means when an acceleration-deceleration rate of said AC motor detected by said rate detector means exceeds a specified value and for controlling the control lead angle to be substantially constant when said acceleration-deceleration rate drops below said specified value.
Claim 2
Dependent Claim
187 words
A control system for controlling the operation of an AC motor, comprising: converter means for converting an AC current from a power source into a DC current; phase control means for controlling said converter means; reactor means for smoothing a DC current output from said converter means; inverter means for converting the smoothed DC current output into an AC current output, said inverter means adapted to drive said AC motor by means of said AC current output; means for detecting an overlapped angle of said AC current signal supplied to said converter means; rate detector means for at least detecting the acceleration-deceleration rate of said AC motor; overlapped angle setter means for setting an overlapped angle of said inverter means to a specified value; and means for controlling a control lead angle of said inverter means in accordance with the overlapped angle set by said overlapped angle setter means when an acceleration-deceleration rate of said AC motor detected by said rate detector means exceeds a specified value and for controlling the control lead angle to be substantially constant when said acceleration-deceleration rate drops below said specified value.
Claim 3
Dependent Claim
143 words
A control system for controlling the operation of an AC motor, comprising: converter means for converting an AC current from a power source into a DC current; phase control means for controlling said converter means; reactor means for smoothing a DC current output from said converter means; inverter means for converting the smoothed DC current output into an AC current output, said inverter means adapted to drive said AC motor by means of said AC output current; rate detector means for detecting at least an acceleration-deceleration rate of said AC motor; means for controlling a commutation marginal angle γ to be substantially constant within a specified operation range of said AC motor at least when the detected acceleration-deceleration rate exceeds a specified value and for controlling a commutation marginal time to be substantially constant when said acceleration-deceleration rate drops below said specified value.
Claim 4
Dependent Claim
143 words
A control system for controlling the operation of an AC motor, comprising: converter means for converting an AC current from a power source into a DC current; phase control means for controlling said converter means; reactor means for smoothing a DC current output from said converter means; inverter means for converting the smoothed DC current output into an AC current output, said inverter means adapted to drive said AC motor by means of said AC output current; rate detector means for detecting at least an acceleration-deceleration rate of said AC motor; means for controlling a commutation marginal angle γ to be substantially constant within a specified operation range of said AC motor at least when the detected acceleration-deceleration rate exceeds a specified value and for controlling a commutation marginal time to be substantially constant when said acceleration-deceleration rate drops below said specified value.
Claim 5
Dependent Claim
60 words
A control system according to claim 1, wherein the acceleration-deceleration rate detector detects said acceleration-deceleration rate based on a detected value of at least one of said AC current from said power source, a change rate of said AC current from said power source, motor speed, a motor speed command change rate and a combination of selected of said values.
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) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |