US6316904B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speed and rotor time constant estimation for torque control of an induction motor
Assignee: Ford Global Technologies LLC
•
Filing: 2000-06-27
•
Granted: 2001-11-13
•
Expires: 2020-06-27
Abstract
Abstract A speed sensorless controller for an induction motor with rotor resistance estimation, using stator currents and voltages. The rotor resistance and speed estimation are obtained as a solution of a linear algebraic system with pseudo current and voltage signals and their observable derivatives as inputs. The proposed scheme provides accurate, real-time estimation of the speed and rotor time constants in all motor operational modes. It can also be used for real-time motor tuning if a speed signal is available.
Inventors
- 👤 Sergey Gennadievich Semenov
- 👤 Alexander Timofeevich Zaremba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:10
CPC Classifications
B; B60; B60L; B60L15/00; B60L15/02; B60L15/025; H; H02; H02P; H02P21/00; H02P21/14; H02P21/16; H02P21/18; H02P21/24; H02P21/26; B60L2200/00; B60L2200/26; B60L2220/00; B60L2220/10; B60L2220/12; H02P2207/00; H02P2207/01; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/64
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
122 words
A method and strategy for estimates of rotor resistance and speed for torque control of an electric induction motor, the motor having a stationary stator with pole pairs in a frame surrounding a rotor wherein only stator current and stator voltage are measurable, the method and strategy comprising the steps of: computing a rotor slip gain as a function of a measurable stator current and a stator voltage; estimating rotor speed; computing orientation and magnitude of rotor flux as a function of stator current, estimated speed and rotor slip gain; and computing a rotor slip speed as a function of slip gain; calculating electrical rotor speed as a function of the number of pole pairs, estimated rotor speed and rotor slip speed.
Claim 2
Independent Claim
122 words
A method and strategy for estimates of rotor resistance and speed for torque control of an electric induction motor, the motor having a stationary stator with pole pairs in a frame surrounding a rotor wherein only stator current and stator voltage are measurable, the method and strategy comprising the steps of: computing a rotor slip gain as a function of a measurable stator current and a stator voltage; estimating rotor speed; computing orientation and magnitude of rotor flux as a function of stator current, estimated speed and rotor slip gain; and computing a rotor slip speed as a function of slip gain; calculating electrical rotor speed as a function of the number of pole pairs, estimated rotor speed and rotor slip speed.
Claim 3
Dependent Claim
22 words
The method and strategy set forth in claim 1 wherein slip gain is equal to rotor resistance divided by rotor inductance γ.
Claim 4
Dependent Claim
98 words
The method and strategy set forth in claim 1 wherein the estimation of rotor speed comprises the step of computing quotient of term b G t Ja′ G and term |b G | 2 , where b G t =−i s1 +δRsi s0 +δu 0 , (i s1 =first pseudo derivative of stator current)+δR s i s0 +δu 0 , a′ G =i s2 +γi s1 −δu 1 (i s2 =second pseudo derivative of stator current)+γi s1 −δu 1 (first pseudo derivative of stator voltage), J is the skew matrix ( 0 - 1 1 0 ) .
Claim 5
Dependent Claim
59 words
The method and strategy set forth in claim 3 wherein slip gain is estimated using the step of computing the quotient of the term b G t Ja′ G and the term |b G | 2 , where b G t =−i s1 +δR s i s0 +δu 0 , a′ G =i s2 +γi s1 −δu 1 .
Claim 6
Dependent Claim
193 words
The method and strategy set forth in claim 3 wherein the estimate of rotor speed comprises the step of obtaining a filtered current and a filtered voltage for the stator from which pseudo derivative values for stator current (i s1 ) and voltage (u 1 ) ( t + G ) 2 i s0 = i s , ( t + G ) 2 u 0 = u i s1 =di s0 dt, i s2 =d 2 i s0 /dt 2 , u 1 =du 0 /dt, which are solutions of the following equations: ( t + G ) 2 i s1 = i s / t , ( t + G ) 2 u 1 = u / t , i s2 =i s −2 Gi s1 −G 2 i s0 , where u=stator voltage u 0 =filtered stator voltage G=filter constant i s =stator current i s0 =filtered stator current i s1 =first pseudo derivative of stator current i s2 =second pseudo derivative of stator current, and u 1 =first pseudo derivative of stator voltage.
Claim 7
Dependent Claim
198 words
The method and strategy set forth in claim 4 wherein the estimate of rotor speed comprises the step of obtaining a filtered current and a filtered voltage for the stator from which pseudo derivative values for stator current (i s1 ) and voltage (u 1 ) respectively, are computed as follows: ( t + G ) 2 i s0 = i s , ( t + G ) 2 u 0 = u i s1 =di s0 dt, i s2 =d 2 i s0 /dt 2 , u 1 =du 0 /dt, which are solutions of the following equations: ( t + G ) 2 i s1 = i s / t , ( t + G ) 2 u 1 = u / t , i s2 =i s −2 Gi s1 −G 2 i s0 , where u=stator voltage u 0 =filtered stator voltage G=filter constant i s =stator current i s0 =filtered stator current i s1 =first pseudo derivative of stator current i s2 =second pseudo derivative of stator current, and u 1 =first pseudo derivative of stator voltage.
References Cited (Backward Citations)
US4445080A
Cited
US4926105A
Cited
US4962339A
Cited
US5032771A
Cited
US5510689A
Cited
US5272429A
Cited
US5334923A
Cited
US5476158A
Cited
US5594670A
Cited
US5541488A
Cited
US5903129A
Cited
US5729113A
Cited
US5796236A
Cited
US6008618A
Cited
US6014006A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-11-12 | 2005-05-14 | 2005-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-11-12 | 2009-05-14 | 2009-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-11-12 | 2013-05-14 | 2013-11-13 | $7700.00 | Window Closed / Lapsed |