US6433506B1
Expired / Lapsed
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Sensorless control system for induction motor employing direct torque and flux regulation
Assignee: Ford Global Technologies LLC
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Filing: 2001-03-29
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Granted: 2002-08-13
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Expires: 2021-03-29
Abstract
Abstract A sensorless control system for an induction motor employs direct tracking of torque and flux regulation to achieve improved motor control without the need for transformation to the rotor flux related frame. A novel torqueflux dynamic model used to implement the control method employs stator voltage as an input, and achieves separation of torque and flux regulation. An alternate regulation method better suited for slow reference signals relies on a steady state solution of the dynamic model.
Inventors
- 👤 Alexey Pavlov
- 👤 Alexander T Zaremba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:14
CPC Classifications
H; H02; H02P; H02P21/00; H02P21/13; H02P21/14; H02P21/141; H02P21/18; H02P21/24; H02P21/26; H02P21/28; H02P21/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
64 words
A method of controlling torque of a multi-phase induction motor based on direct tracking of the motor's torque and flux, comprising: (a) estimating rotor speed of said motor; (b) estimating rotor flux from said estimated rotor speed and stator current; (c) estimating rotor torque from said estimated rotor flux; and (d) using the estimated rotor torque and estimated rotor flux to control said motor.
Claim 2
Independent Claim
64 words
A method of controlling torque of a multi-phase induction motor based on direct tracking of the motor's torque and flux, comprising: (a) estimating rotor speed of said motor; (b) estimating rotor flux from said estimated rotor speed and stator current; (c) estimating rotor torque from said estimated rotor flux; and (d) using the estimated rotor torque and estimated rotor flux to control said motor.
Claim 3
Dependent Claim
39 words
The method of claim 1 , wherein step (a) includes estimating said rotor speed as a function of first and second order derivatives of a filtered stator current signal and first order derivative of a filtered stator voltage signal.
Claim 4
Dependent Claim
23 words
The method of claim 1 , wherein step (b) is performed using the combination of said estimated rotor speed and the stator current.
Claim 5
Dependent Claim
15 words
The method of claim 1 , wherein step (a) is performed using a position sensor.
Claim 6
Dependent Claim
24 words
The method of claim 1 , wherein step (a) is performed by estimating speed as a function of filtered stator current and voltage signals.
Claim 7
Dependent Claim
239 words
The method of claim 1 , wherein step (d) is performed based on a steady state solution of the following equations υ ~ 1 = ( k - σ σ L s ) T ref + μ ( ( M σ L s L r + 1 M ) n p ω - β MσL s ) F ref υ ~ 2 = - 1 μ ( n p ω - β σ L s ) T ref + ( R r ML r + R s σ L s M - α MσL s ) F ref . wherein: {tilde over (v)} 1 ,{tilde over (v)} 2 are voltages k is k = R r L r + 1 σ L s ( R s + M 2 R r L r 2 ) . σ is 1−M 2 /L s L r —leakage parameter T ref is the reference torque μ is 3n p M/2L r M is mutual inductance L s ,L r are stator and rotor inductance, respectively n p is number of pole pairs ω is angular speed of the rotor β is parameter chosen so that the state matrix is stable F ref is the flux reference value R r ,R s are rotor and stator resistance, respectively.
Claim 8
Dependent Claim
201 words
The method of claim 1 , wherein step (d) is performed based on a steady state solution of the following equations υ s = λ r λ r υ sd + Jλ r λ r υ sq + α i s + β Ji s , υ sd = σ L s λ r ( υ ~ 2 - R r M L r i s 2 ) , υ sq = σ L s μ λ r υ ~ 1 . wherein: v s is voltage v sd is voltage λ r is rotor flux J is ( 0 - 1 1 0 ) ν sq is the component of stator voltage orthogonal to the rotor flux α,β ad are parameters chosen so that the state matrix is stable i s is stator current are voltages defined by equation 37 R r is rotor resistance M is mutual inductance, L r is rotor inductance L s is stator inductance μ is 3n p M/2L r .
Claim 9
Dependent Claim
248 words
The method of claim 1 , wherein step (d) is performed using a dynamic torque-flux model defined by the following equation Z t = [ - k - μ Mn p w σ L s L r - μ n p w 0 - 2 R r L r 2 R r M L r n p w μ MR r σ L s L r 2 - k ] Z + [ μ σ L s λ r υ sq 0 R r M L r i s 2 + 1 σ L s λ r υ sd ] . wherein: Z is new state vector k is k = R r L r + 1 σ L s ( R s + M 2 R r L r 2 ) . μ is 3n p M/2L r M is mutual inductance n p is number of pole pairs ω is angular speed of the rotor σ is 1−M 2 /L s L r —leakage parameter L s ,L r are stator and rotor inductance, respectively R r is rotor resistance λ r is rotor flux ν sq is the component of stator voltage orthogonal to the rotor flux i s is stator current v sd is voltage.
Claim 10
Dependent Claim
201 words
The method of claim 1 , wherein step (d) is performed by commanded said motor with by a voltage given by the following equations υ ^ sd = - L ~ FD ( - λ ^ r 2 + M λ ^ r T i s ) - L ~ FP ( λ ^ r 2 - F ref ) υ ^ sq = - L ~ TP ( T ^ e - T ref ) - L ^ Tl ∫ 0 t ( T ^ e T ref ) s . where v sd is estimated component of the stator voltage L fd is gain of the controller {circumflex over (λ)} r is estimated rotor flux M is mutual inductance λ r T is estimated transposed rotor flux i s is stator current is gain of the controller F ref is the flux reference value ν sq is the component of stator voltage orthogonal to the rotor flux L TP is the gain of the PI controller T e is estimated electromagnetic torque T ref is reference torque L TI is estimated gain of the PI controller.
Claim 11
Dependent Claim
248 words
The method of claim 1 , wherein step (d) is performed by determining a steady state solution of the following equation Z t = [ - k - μ Mn p ω σ L s L r - μ n p ω 0 - 2 R r L r 2 R r M L r n p ω μ MR r σ L s L r 2 - k ] Z + [ - μ σ L s λ r T J υ s 0 R r M L r i s 2 + 1 σ L s λ r T υ s ] . wherein: Z is new state vector k is k = R r L r + 1 σ L s ( R s + M 2 R r L r 2 ) . μ is 3n p M/2L r M is mutual inductance n p is number of pole pairs ω is angular speed of the rotor σ is 1−M 2 /L s L r —leakage parameter L s ,L r are stator and rotor inductance, respectively R r is rotor resistance λ r T is estimated transposed rotor flux J is ( 0 - 1 1 0 ) v s is voltage.
References Cited (Backward Citations)
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