US5166593A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Closed-loop torque feedback for a universal field-oriented controller
Assignee: General Electric Co
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Filing: 1991-10-02
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Granted: 1992-11-24
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Expires: 2011-10-02
Abstract
Abstract A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation.
Inventors
- 👤 Rik W. A. A. De Doncker
- 👤 Robert D. King
- 👤 Peter C. Sanza
- 👤 Kenneth B. Haefner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:39
CPC Classifications
H; H02; H02P; H02P21/00; H02P21/06; G; G05; G05B; G05B11/00; G05B11/01; G05B11/26; G05B11/28
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
159 words
A torque feedback system for a field-oriented controller for an induction motor, comprising: flux sensing means for sensing the direct and quadrature components and Ψ d s and Ψ q s , respectively, of flux in a stationary reference frame linked to a predetermined phase of the induction motor; current sensing means for sensing the respective stator phase currents in at least two phases of the induction motor in a stationary reference frame linked to a predetermined phase of the induction motor; torque-calculating means for calculating torque T em from the sensed components of flux and the sensed stator phase currents; comparator means for comparing the torque from said torque-calculating means to a torque command and generating a difference signal therefrom; a first torque feedback loop for receiving said difference signal and tuning a current command in accordance therewith; and a second torque feedback loop for receiving said difference signal and tuning a slip frequency command in accordance therewith.
Claim 2
Dependent Claim
159 words
A torque feedback system for a field-oriented controller for an induction motor, comprising: flux sensing means for sensing the direct and quadrature components and Ψ d s and Ψ q s , respectively, of flux in a stationary reference frame linked to a predetermined phase of the induction motor; current sensing means for sensing the respective stator phase currents in at least two phases of the induction motor in a stationary reference frame linked to a predetermined phase of the induction motor; torque-calculating means for calculating torque T em from the sensed components of flux and the sensed stator phase currents; comparator means for comparing the torque from said torque-calculating means to a torque command and generating a difference signal therefrom; a first torque feedback loop for receiving said difference signal and tuning a current command in accordance therewith; and a second torque feedback loop for receiving said difference signal and tuning a slip frequency command in accordance therewith.
Claim 3
Dependent Claim
131 words
The torque feedback system of claim 1 wherein the induction motor has three stator phases and current is sensed by said current sensing means in two of said stator phases, the torque being calculated by said torque-calculating means according to the expression: ##EQU12## wherein p represents the number of pole pairs of the induction motor, and wherein one of the two sensed phases is chosen as the reference phase so that the d component of current i sd s is equal to the phase current i s a sensed on said one of said phases, and the q component of current i sq s is determined according to the expression: ##EQU13## wherein the phase current sensed on the second one of the sensed phases is represented by i s b .
Claim 4
Dependent Claim
16 words
The torque feedback system of claim 1 wherein the said flux sensing means comprises flux coils.
Claim 5
Dependent Claim
65 words
The torque feedback system of claim 1 wherein said flux sensing means comprises: voltage sensing means for sensing the stator voltage V s across the respective stator phase winding; and flux estimating means for providing an estimate of the flux Ψ according to: ##EQU14## where R s is the resistance of the respective stator phase winding, and I s is the respective stator phase current.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-11-24 | 1996-05-25 | 1996-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-24 | 2000-05-25 | 2000-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-24 | 2004-05-25 | 2004-11-24 | $7700.00 | Window Closed / Lapsed |