Patent US4605885A successfully refreshed from Google Patents.
US4605885A
Expired / Lapsed
US
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Method of controlling rotation speed of motor
Assignee: Mitsubishi Electric Corp
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Filing: 1985-07-03
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Granted: 1986-08-12
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Expires: 2005-07-03
Abstract
Abstract A method of controlling the rotation speed of a motor to maintain it at a desired value, comprising a step of obtaining a deviation between the detected rotation speed and the desired value, and a step of changing the gain of a feedback loop, which serves to control the current flowing in the motor, to a value lower than a predetermined one during a period in which the deviation of the detected deviation in rotation speed is smaller than a preset maximum ripple value.
Inventors
- 👤 Masamichi Mitsuhashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:29
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/2855; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/906
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
197 words
A method of controlling the rotation speed of a motor comprising the steps of: detecting a deviation between the rotation speed detected by a speed sensor and a desired rotation speed; detecting a difference between a detected current flowing in said motor and a current reference signal obtained through a computation executed in a speed controller on the basis of said deviation, and subsequently; controlling the motor current in accordance with a signal obtained through a computation executed in a current controller on the basis of said difference, thereby maintaining the rotation speed of said motor at a desired value; comparing a maximum ripple value with said deviation; setting the gain of said speed controller at a predetermined first value, in response to the comparing step indicating said deviation is greater than said maximum ripple value, to provide for fast response in controlling the motor rotation speed; and setting the gain of said speed controller at a second value which is lower than said predetermined first value, in response to the comparing step indicating that said deviation is smaller than said maximum ripple value, to stabilize speed control by avoiding fast adjustments in speed due to ripple.
Claim 2
Independent Claim
197 words
A method of controlling the rotation speed of a motor comprising the steps of: detecting a deviation between the rotation speed detected by a speed sensor and a desired rotation speed; detecting a difference between a detected current flowing in said motor and a current reference signal obtained through a computation executed in a speed controller on the basis of said deviation, and subsequently; controlling the motor current in accordance with a signal obtained through a computation executed in a current controller on the basis of said difference, thereby maintaining the rotation speed of said motor at a desired value; comparing a maximum ripple value with said deviation; setting the gain of said speed controller at a predetermined first value, in response to the comparing step indicating said deviation is greater than said maximum ripple value, to provide for fast response in controlling the motor rotation speed; and setting the gain of said speed controller at a second value which is lower than said predetermined first value, in response to the comparing step indicating that said deviation is smaller than said maximum ripple value, to stabilize speed control by avoiding fast adjustments in speed due to ripple.
Claim 3
Dependent Claim
42 words
The method as defined in claim 1, wherein said speed controller has a proportional-plus-integral function and, during a period in which said deviation is smaller than said maximum ripple value, the proportional gain of said funtion is held at a lower value.
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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) | 1989-08-11 | 1990-02-10 | 1990-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-11 | 1994-02-10 | 1994-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-11 | 1998-02-10 | 1998-08-12 | $7700.00 | Window Closed / Lapsed |