US6509711B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital rotor flux observer
Assignee: Ford Global Technologies LLC
•
Filing: 2000-04-26
•
Granted: 2003-01-21
•
Expires: 2020-04-26
Abstract
Abstract A system ( 10 ) for controlling the torque of an induction motor ( 12 ) utilizes a flux observer ( 14 ). The flux observer ( 14 ) receives stator current inputs ( 16, 18 ) and a rotor speed estimate ( 80 ) and then outputs a rotor flux estimate ( 20 ) that provides increased motor control stability at all speeds.
Inventors
- 👤 Alexander Timofeevich Zaremba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:15
CPC Classifications
H; H02; H02P; H02P21/00; H02P21/14; H02P21/141
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
105 words
A method of utilizing a rotor flux observer to control the torque of an induction motor, having a rotor and a stator, comprising: receiving a signal indicative of the stator current at the rotor flux observer; receiving a signal representative of the rotor speed at the rotor flux observer; calculating an exponent of said rotor speed signal; estimating the rotor flux based on the assumption that the rotor speed is constant over a sampling interval determining a discrete form of the rotor flux; estimating a rotor flux angle; calculating a voltage to be used in controlling the motor torque, based on a field orientation scheme.
Claim 2
Independent Claim
105 words
A method of utilizing a rotor flux observer to control the torque of an induction motor, having a rotor and a stator, comprising: receiving a signal indicative of the stator current at the rotor flux observer; receiving a signal representative of the rotor speed at the rotor flux observer; calculating an exponent of said rotor speed signal; estimating the rotor flux based on the assumption that the rotor speed is constant over a sampling interval determining a discrete form of the rotor flux; estimating a rotor flux angle; calculating a voltage to be used in controlling the motor torque, based on a field orientation scheme.
Claim 3
Independent Claim
247 words
A method of utilizing a rotor flux observer to control the torque of an induction motor, having a rotor and a stator, comprising: receiving a signal indicative of the stator current at the rotor flux observer; receiving a signal representative of the rotor speed at the rotor flux observer; calculating an exponent of said rotor speed signal; estimating the rotor flux based on the assumption that the rotor speed is constant over a sampling interval; determining a discrete form of the rotor flux; recovering scalar components of the rotor flux to obtain a flux estimated volume, wherein said scalar components of the rotor flux are determined according to the following equations: λ rx ( k + 1 ) = ( 1 - α ) λ rxk - βλ ryk + η M η 2 + ω r 2 [ ( ηa + ω r β ) i sx - ( ω r a - ηβ ) i sy ] λ ry ( k + 1 ) = ( 1 - α ) λ ryk + βλ rxk + η M η 2 + ω r 2 [ ( ηa + ω r β ) i sy - ( ω r a - ηβ ) i sx ] estimating a rotor flux angle; calculating a voltage to be used in controlling the motor torque, based on a field orientation scheme.
Claim 4
Independent Claim
247 words
A method of utilizing a rotor flux observer to control the torque of an induction motor, having a rotor and a stator, comprising: receiving a signal indicative of the stator current at the rotor flux observer; receiving a signal representative of the rotor speed at the rotor flux observer; calculating an exponent of said rotor speed signal; estimating the rotor flux based on the assumption that the rotor speed is constant over a sampling interval; determining a discrete form of the rotor flux; recovering scalar components of the rotor flux to obtain a flux estimated volume, wherein said scalar components of the rotor flux are determined according to the following equations: λ rx ( k + 1 ) = ( 1 - α ) λ rxk - βλ ryk + η M η 2 + ω r 2 [ ( ηa + ω r β ) i sx - ( ω r a - ηβ ) i sy ] λ ry ( k + 1 ) = ( 1 - α ) λ ryk + βλ rxk + η M η 2 + ω r 2 [ ( ηa + ω r β ) i sy - ( ω r a - ηβ ) i sx ] estimating a rotor flux angle; calculating a voltage to be used in controlling the motor torque, based on a field orientation scheme.
Claim 5
Dependent Claim
34 words
The method of claim 1 , wherein said rotor flux angle is estimated according to the following equation: cos θ ^ r = λ ry λ ry 2 + λ ry 2
Claim 6
Dependent Claim
18 words
The flux observer of claim 2 , wherein said rotor speed signal is received from a speed observer.
Claim 7
Dependent Claim
26 words
The flux observer of claim 4 , wherein said speed observer receives current inputs and voltage inputs from a current observer and a voltage observer respectively.
Claim 8
Dependent Claim
35 words
The flux observer of claim 2 , wherein said rotor flux angle is determined according to the following equation: cos θ ^ r = λ ry λ ry 2 + λ ry 2
Claim 9
Dependent Claim
137 words
A discrete time flux observer for torque control of an induction motor, the induction motor having a rotor and a stator, comprising: a rotor speed input for receiving a signal indicative of the rotor speed; a stator current input for receiving a signal indicative of the stator current; a rotor flux estimating mechanism that estimates the rotor flux based on the assumption that the rotor speed is constant over a sampling interval; a rotor flux output for outputting said estimated rotor flux; a flux angle calculation for receiving said estimated rotor flux and determining a rotor flux angle; and a field oriented controller for receiving said determined rotor flux angle and determining a stator voltage; wherein the flux observer is used to control an induction motor that is incorporated into a vehicle electronic power assisted steering system.
Claim 10
Dependent Claim
137 words
A discrete time flux observer for torque control of an induction motor, the induction motor having a rotor and a stator, comprising: a rotor speed input for receiving a signal indicative of the rotor speed; a stator current input for receiving a signal indicative of the stator current; a rotor flux estimating mechanism that estimates the rotor flux based on the assumption that the rotor speed is constant over a sampling interval; a rotor flux output for outputting said estimated rotor flux; a flux angle calculation for receiving said estimated rotor flux and determining a rotor flux angle; and a field oriented controller for receiving said determined rotor flux angle and determining a stator voltage; wherein the flux observer is used to control an induction motor that is incorporated into a vehicle electronic power assisted steering system.
Claim 11
Dependent Claim
53 words
The flux observer of claim 7 , wherein a discrete form of said rotor flux observer is expressed as follows: λ rk + 1 = λ k e - σ T + η M i sk i - e - σ T σ
Claim 12
Dependent Claim
139 words
The flux observer of claim 8 , wherein the rotor flux observer analytical digital form is determined as follows: λ rx ( k + 1 ) = ( 1 - α ) λ rxk - βλ ryk + η M η 2 + ω r 2 [ ( ηα + ω r β ) i sx - ( ω r α - ηβ ) i sy ] λ ry ( k + 1 ) = ( 1 - α ) λ ryk - βλ rxk + η M η 2 + ω r 2 [ ( ηα + ω r β ) i sy - ( ω r α - ηβ ) i sx ] . ( 8 )
Claim 13
Dependent Claim
47 words
The control scheme of claim 9 , wherein the flux observer receives a pair of current inputs with the first current input being representative of the x component of the stator current and the second current input being representative of the y component of the stator current.
Claim 14
Dependent Claim
26 words
The control scheme of claim 9 , wherein said flux observer output or estimated rotor flux which is then used to determine a rotor flux angle.
Claim 15
Dependent Claim
57 words
The control scheme of claim 11 , wherein a discrete form of said rotor flux is expressed in accordance with the following equation: λ rk + 1 = λ k - σ T + η M i sk 1 - - σ T σ .
Claim 16
Dependent Claim
140 words
The control scheme of claim 12 , wherein an analytical digital form of said flux observer is determined as follows: λ rx ( k + 1 ) = ( 1 - α ) λ rxk - βλ ryk + η M η 2 + ω r 2 [ ( ηα + ω r β ) i sx - ( ω r α - ηβ ) i sy ] λ ry ( k + 1 ) = ( 1 - α ) λ ryk - βλ rxk + η M η 2 + ω r 2 [ ( ηα + ω r β ) i sy - ( ω r α - ηβ ) i sx ] . ( 8 )
Claim 17
Dependent Claim
137 words
A sensorless field orientation control scheme for controlling an induction motor, comprising: a flux observer for determining a rotor flux; a speed observer in communication with said flux observer to provide said flux observer with a signal indicative of the rotor speed; a voltage observer in communication with said speed observer to provide said speed observer with a signal representative of the filtered motor voltage; a current observer to provide said speed observer with a signal representative of the filtered motor current; and a field oriented controller in communication with said flux observer to control the torque of the motor; whereby said flux observer estimates said motor flux based on the assumption that the motor speed is constant over a sampling interval and wherein the inductive motor is incorporated into a vehicle electronic power assisted steering system.
Claim 18
Dependent Claim
137 words
A sensorless field orientation control scheme for controlling an induction motor, comprising: a flux observer for determining a rotor flux; a speed observer in communication with said flux observer to provide said flux observer with a signal indicative of the rotor speed; a voltage observer in communication with said speed observer to provide said speed observer with a signal representative of the filtered motor voltage; a current observer to provide said speed observer with a signal representative of the filtered motor current; and a field oriented controller in communication with said flux observer to control the torque of the motor; whereby said flux observer estimates said motor flux based on the assumption that the motor speed is constant over a sampling interval and wherein the inductive motor is incorporated into a vehicle electronic power assisted steering system.
Claim 19
Dependent Claim
36 words
The control scheme of claim 11 , wherein said rotor flux angle is determined according to the following equation: cos θ ^ r = λ ry λ ry 2 + λ ry 2 .
References Cited (Backward Citations)
US4707651A
Cited
US5296793A
Cited
US4777422A
Cited
US5296794A
Cited
US5796235A
Cited
US5365158A
Cited
US5585709A
Cited
US5708346A
Cited
US5541488A
Cited
US5729113A
Cited
US5796236A
Cited
US5973474A
Cited
US6137258A
Cited
US6069467A
Cited
US6014006A
Cited
US6163127A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2006-01-20 | 2006-07-22 | 2007-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-01-20 | 2010-07-22 | 2011-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-01-20 | 2014-07-22 | 2015-01-21 | $7700.00 | Window Closed / Lapsed |