Patent US4862343A successfully refreshed from Google Patents.
US4862343A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Induction motor control apparatus
Assignee: Meidensha Corp
•
Filing: 1988-02-16
•
Granted: 1989-08-29
•
Expires: 2008-02-16
Abstract
Abstract An induction motor vectro control apparatus calculates a slip factor using a secondary time constant. A reference signal is added as noise to the excitation current command signal. The secondary time constant is brought closer to its actual value by modifying the secondary time constant in a direction zeroing the correlation between the motor speed feedback signal and the reference signal.
Inventors
- 👤 Masakatsu Nomura
- 👤 Keiko Suda
- 👤 Tadashi Ashikaga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:51
CPC Classifications
H; H02; H02P; H02P5/00; H02P21/00; H02P21/06; H02P21/08; H02P21/09; H02P21/36
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
246 words
An apparatus for vector control of an adjustable-speed induction motor, including a motor drive circuit for applying power to drive the motor, and a control circuit responsive to a torque command signal, an excitation current command signal and a slip frequency for controlling the operation of the motor drive circuit so as to vary the power to the motor, the control circuit including: a speed sensor sensitive to motor rotation speed for producing a speed feedback signal indicative of a sensed speed of rotation of the motor; a source for producing a speed command signal indicative of a desired motor speed; a source for producing an excitation current command signal indicative of a desired motor excitation current; a source for producing a reference signal; means for summing the speed feedback signal and the speed command signal to provide a speed error signal indicative of the difference between the sensed and desired motor speeds; means for converting the speed error signal into the torque command signal; means for adding the reference signal to the excitation current command signal applied to the control circuit; means responsive to the excitation current command signal and the torque command signal for calculating the slip frequency using a secondary time constant; means for calculating a correlation coefficient indicative of a mutual relation between the speed error signal and the reference signal; and means for modifying the secondary time constant, in accordance with the correlation coefficient, in a direction zeroing the correlation coefficient.
Claim 2
Independent Claim
246 words
An apparatus for vector control of an adjustable-speed induction motor, including a motor drive circuit for applying power to drive the motor, and a control circuit responsive to a torque command signal, an excitation current command signal and a slip frequency for controlling the operation of the motor drive circuit so as to vary the power to the motor, the control circuit including: a speed sensor sensitive to motor rotation speed for producing a speed feedback signal indicative of a sensed speed of rotation of the motor; a source for producing a speed command signal indicative of a desired motor speed; a source for producing an excitation current command signal indicative of a desired motor excitation current; a source for producing a reference signal; means for summing the speed feedback signal and the speed command signal to provide a speed error signal indicative of the difference between the sensed and desired motor speeds; means for converting the speed error signal into the torque command signal; means for adding the reference signal to the excitation current command signal applied to the control circuit; means responsive to the excitation current command signal and the torque command signal for calculating the slip frequency using a secondary time constant; means for calculating a correlation coefficient indicative of a mutual relation between the speed error signal and the reference signal; and means for modifying the secondary time constant, in accordance with the correlation coefficient, in a direction zeroing the correlation coefficient.
Claim 3
Dependent Claim
54 words
The apparatus as claimed in claim 1, wherein the correlation coefficient calculating means includes a multiplier for multiplying the speed error signal by the reference signal to produce a multiplied signal indicative of the resulting product, and a primary delay circuit connected to the multiplier for producing a signal indicative of the correlation coefficient.
Claim 4
Dependent Claim
50 words
The apparatus as claimed in claim 2, wherein the secondary time constant modifying means includes means for integrating the correlation coefficient indication signal to provide a signal indicative of the reciprocal of the secondary time constant, the secondary time constant indication signal having a sign determined by the reference signal.
Claim 5
Dependent Claim
79 words
The apparatus as claimed in claim 3, wherein the slip frequency calculating means includes means for dividing the torque command signal by the excitation current command signal to produce a divided signal indicative of the resulting quotient, means for loading the secondary time constant indication signal fed thereto from the secondary time constant modifying means, and means for multiplying the divided signal by the loaded secondary time constant indication signal to produce a signal indicative of the slip frequency.
Claim 6
Dependent Claim
86 words
The apparatus as claimed in claim 3, wherein the slip frequency calculating means includes means for dividing the torque command signal by the sum of the excitation current command signal and the reference signal to produce a divided signal indicative of the resulting quotient, means for loading the secondary time constant indication signal fed thereto from the secondary time constant modifying means, and means for multiplying the divided signal by the loaded secondary time constant indication signal to produce a signal indicative of the slip frequency.
Claim 7
Independent Claim
254 words
An apparatus for vector control of an adjustable-speed induction motor, including a motor drive circuit for applying power to drive the motor, and a control circuit responsive to a torque command signal, an excitation current command signal and a slip frequency for controlling the operation of the motor drive circuit so as to vary the power to the motor, the control circuit including: a speed sensor sensitive to motor rotation speed for producing a speed feedback signal indicative of a sensed speed of rotation of the motor; a source for producing a speed command signal indicative of a desired motor speed; a source for producing an excitation current command signal indicative of a desired motor excitation current; a source for producing a reference signal; means for summing the speed feedback signal and the speed command signal to provide a speed error signal indicative of the difference between the sensed and desired motor speeds; means for converting the speed error signal into the torque command signal; means for adding the reference signal to the excitation current command signal applied to the control circuit; means responsive to the excitation current command signal and the torque command signal for calculating the slip frequency using a secondary time constant; means for calculating a correlation coefficient indicative of a mutual relation between the reference signal and a signal related to the sensed speed of rotation of the motor; and means for modifying the second time constant, in accordance with the correlation coefficient, in a direction zeroing the correlation coefficient.
Claim 8
Independent Claim
254 words
An apparatus for vector control of an adjustable-speed induction motor, including a motor drive circuit for applying power to drive the motor, and a control circuit responsive to a torque command signal, an excitation current command signal and a slip frequency for controlling the operation of the motor drive circuit so as to vary the power to the motor, the control circuit including: a speed sensor sensitive to motor rotation speed for producing a speed feedback signal indicative of a sensed speed of rotation of the motor; a source for producing a speed command signal indicative of a desired motor speed; a source for producing an excitation current command signal indicative of a desired motor excitation current; a source for producing a reference signal; means for summing the speed feedback signal and the speed command signal to provide a speed error signal indicative of the difference between the sensed and desired motor speeds; means for converting the speed error signal into the torque command signal; means for adding the reference signal to the excitation current command signal applied to the control circuit; means responsive to the excitation current command signal and the torque command signal for calculating the slip frequency using a secondary time constant; means for calculating a correlation coefficient indicative of a mutual relation between the reference signal and a signal related to the sensed speed of rotation of the motor; and means for modifying the second time constant, in accordance with the correlation coefficient, in a direction zeroing the correlation coefficient.
Claim 9
Dependent Claim
30 words
The apparatus as claimed in claim 6, wherein the correlation coefficient calculating means calculates a correlation coefficient of a mutual relation between the reference signal and the speed feedback signal.
Claim 10
Dependent Claim
54 words
The apparatus as claimed in claim 7, wherein the correlation coefficient calculating means includes a multiplier for multiplying the speed feedback signal by the reference signal to produce a multiplied signal indicative of the resulting product, and a primary delay circuit connected to the multiplier for producing a signal indicative of the correlation coefficient.
Claim 11
Dependent Claim
50 words
The apparatus as claimed in claim 8, wherein the secondary time constant modifying means includes means for integrating the correlation coefficient indication signal to provide a signal indicative of the reciprocal of the secondary time constant, the secondary time constant indication signal having a sign determined by the reference signal.
Claim 12
Dependent Claim
79 words
The apparatus as claimed in claim 9, wherein the slip frequency calculating means includes means for dividing the torque command signal by the excitation current command signal to produce a divided signal indicative of the resulting quotient, means for loading the secondary time constant indication signal fed thereto from the secondary time constant modifying means, and means for multiplying the divided signal by the loaded secondary time constant indication signal to produce a signal indicative of the slip frequency.
Claim 13
Dependent Claim
86 words
The apparatus as claimed in claim 9, wherein the slip frequency calculating means includes means for dividing the torque command signal by the sum of the excitation current command signal and the reference signal to produce a divided signal indicative of the resulting quotient, means for loading the secondary time constant indication signal fed thereto from the secondary time constant modifying means, and means for multiplying the divided signal by the loaded secondary time constant indication signal to produce a signal indicative of the slip frequency.
References Cited (Backward Citations)
US4377779A
Cited
EP0071847A2
Cited
US4516065A
Cited
US4628475A
Cited
EP0121792A2
Cited
US4615000A
Cited
EP0157202A1
Cited
US4602201A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |