US6605912B1
Expired / Lapsed
US
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Method for controlling a permanent magnet motor
Assignee: Motors Liquidation Co
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Filing: 1998-06-25
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Granted: 2003-08-12
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Expires: 2018-06-25
Abstract
Abstract A three region control strategy for a permanent magnet motor is presented. In a first control region, the permanent magnet motor is operated at, a 120° conduction square wave mode at reduced phase current, and below a no-load speed. The motor phase current commutation causes eddy current losses in the rotor magnets and core which are insignificant due to the low phase currents and relatively low rotor speed. Meanwhile, the inverter switching losses are kept low as two switches are in use (on/off) for each current commutation during the 120° conduction mode. In a second control region, the permanent magnet motor is operated at a 180° conduction sinusoidal wave mode with high phase currents. The 180° conduction sinusoidal wave mode minimizes the commutation loss. In a third control region, the permanent magnet motor is operated above its no-load speed or in a field weakening mode. At these higher speeds the slot ripple and commutation losses on the rotor increase, and the demagnetizing component of the armature reaction increases due to field weakening. Commutation losses are minimized through sinusoidal current operation. In the field weakening mode, the phase current conduction angle is set to 180° and the phase currents become sinusoidal.
Inventors
- 👤 Aravind Sourirajan Bharadwaj
- 👤 Fang Deng
- 👤 Thomas Wolfgang Nehl
- 👤 Malakondaiah Naidu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:38
CPC Classifications
H; H02; H02P; H02P21/00; H02P21/0085; H02P21/0089; H02P6/00; H02P6/14; H02P6/15; H02P2209/00; H02P2209/07
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
197 words
A method of controlling operation of a permanent magnet motor, comprising: selecting a mode of operation from first, second and third modes of operation based on at least one of a signal indicative of a parameter of the motor and a command signal wherein the first and second modes of operation are constant torque modes and the third mode of operation is a field weakening mode; applying to the motor, phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected; applying to the motor, phase currents which are substantially sinusoidal and are substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value; and applying to the motor, phase currents which are substantially out of phase with corresponding electromotive forces of the motor when the third mode of operation is selected; wherein the said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 2
Independent Claim
197 words
A method of controlling operation of a permanent magnet motor, comprising: selecting a mode of operation from first, second and third modes of operation based on at least one of a signal indicative of a parameter of the motor and a command signal wherein the first and second modes of operation are constant torque modes and the third mode of operation is a field weakening mode; applying to the motor, phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected; applying to the motor, phase currents which are substantially sinusoidal and are substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value; and applying to the motor, phase currents which are substantially out of phase with corresponding electromotive forces of the motor when the third mode of operation is selected; wherein the said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 3
Dependent Claim
39 words
The method of claim 1 wherein the phase currents which are generally out of phase with corresponding electromotive forces of the motor comprise sinusoidal phase currents which are substantially out of phase with corresponding electromotive forces of the motor.
Claim 4
Dependent Claim
29 words
The method of claim 1 wherein the permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 5
Dependent Claim
97 words
The method of claim 1 wherein: the phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected comprise essentially 120° phase currents; the phase currents which are substantially sinusoidal and are substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected comprise essentially 180° sinusoidal phase currents; and the phase currents which are substantially out of phase with corresponding electromotive forces of the motor when the third mode of operation is selected comprise essentially 180° phase currents.
Claim 6
Dependent Claim
35 words
The method of claim 1 further comprising: generating the phase currents which are substantially out of phase with corresponding electromotive forces of the motor when the third mode of operation is selected utilizing flux weakening.
Claim 7
Dependent Claim
28 words
The method of claim 5 wherein the utilization of flux weakening includes varying a phase advance angle of the phase currents until a desired operating condition is obtained.
Claim 8
Dependent Claim
20 words
The method of claim 6 wherein the varying the phase angle comprises incrementing the phase angle in essentially 1° increments.
Claim 9
Dependent Claim
24 words
The method of claim 6 wherein the varying the phase angle comprises varying the phase angle up to a phase angle of essentially 90°.
Claim 10
Independent Claim
158 words
A method of controlling operation of a permanent magnet motor, comprising: applying to the motor, phase currents which are substantially in phase with corresponding electromotive forces of the motor when a first mode of operation is selected; applying to the motor, phase currents which are substantially in phase with corresponding electromotive forces of the motor and substantially sinusoidal when a second mode of operation is selected; selecting from said first mode of operation and said second mode of operation based on at least one of a signal indicative of a parameter of the motor and a command signal wherein the first and second modes of operation are constant torque modes, and wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value; and wherein said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 11
Independent Claim
158 words
A method of controlling operation of a permanent magnet motor, comprising: applying to the motor, phase currents which are substantially in phase with corresponding electromotive forces of the motor when a first mode of operation is selected; applying to the motor, phase currents which are substantially in phase with corresponding electromotive forces of the motor and substantially sinusoidal when a second mode of operation is selected; selecting from said first mode of operation and said second mode of operation based on at least one of a signal indicative of a parameter of the motor and a command signal wherein the first and second modes of operation are constant torque modes, and wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value; and wherein said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 12
Dependent Claim
23 words
The method of claim 9 wherein the phase currents of said second mode of operation which are substantially sinusoidal comprise sinusoidal phase currents.
Claim 13
Dependent Claim
20 words
The method of claim 9 wherein the phase currents of said first mode of operation are substantially rectangular phase currents.
Claim 14
Dependent Claim
29 words
The method of claim 9 wherein the permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 15
Dependent Claim
35 words
The method of claim 9 wherein: the phase currents of the first mode of operation comprise essentially 120° phase currents; and the phase currents of the second mode of operation comprise essentially 180° phase currents.
Claim 16
Dependent Claim
35 words
The method of claim 9 further comprising: generating the phase currents which are substantially out of phase with corresponding electromotive forces of the motor when a third mode of operation is selected utilizing flux weakening.
Claim 17
Dependent Claim
28 words
The method of claim 14 wherein the utilization of flux weakening includes varying a phase advance angle of the phase currents until a desired operating condition is obtained.
Claim 18
Dependent Claim
20 words
The method of claim 15 wherein the varying the phase angle comprises incrementing the phase angle in essentially 1° increments.
Claim 19
Dependent Claim
24 words
The method of claim 15 wherein the varying the phase angle comprises varying the phase angle up to a phase angle of essentially 90°.
Claim 20
Dependent Claim
227 words
A permansent magnet motor control system for an electric vehicle, comprising: a permanent magnet motor associated with the electric vehicle; a battery associated with the electric vehicle; an inverter receptive to direct current signals from the battery for providing phase currents to the motor; and a controller for selecting a mode of operation from first, second and third modes of operation, wherein the first and second modes of operation are constant torque modes and the third mode of operation is a field weakening mode, and for producing control signals, based on at least one of a signal indicative of a parameter of the motor and a command signal, the inverter in response to the control signals providing phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected, are sinusoidal and substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value, and are substantially out of phase with corresponding electromotive forces of the motor when the third mode of operation is selected; wherein said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 21
Dependent Claim
227 words
A permansent magnet motor control system for an electric vehicle, comprising: a permanent magnet motor associated with the electric vehicle; a battery associated with the electric vehicle; an inverter receptive to direct current signals from the battery for providing phase currents to the motor; and a controller for selecting a mode of operation from first, second and third modes of operation, wherein the first and second modes of operation are constant torque modes and the third mode of operation is a field weakening mode, and for producing control signals, based on at least one of a signal indicative of a parameter of the motor and a command signal, the inverter in response to the control signals providing phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected, are sinusoidal and substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value, and are substantially out of phase with corresponding electromotive forces of the motor when the third mode of operation is selected; wherein said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 22
Dependent Claim
39 words
The system of claim 18 wherein the phase currents which are substantially out of phase with corresponding electromotive forces of the motor comprise sinusoidal phase currents which are substantially out of phase with corresponding electromotive forces of the motor.
Claim 23
Dependent Claim
29 words
The system of claim 18 wherein the permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 24
Dependent Claim
97 words
The system of claim 18 wherein: the phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected comprise essentially 120° phase currents; the phase currents which are substantially sinusoidal and are substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected comprise essentially 180° sinusoidal phase currents; and the phase currents which are substantially out of phase with corresponding electromotive forces of the motor when the third mode of operation is selected comprise essentially 180° phase currents.
Claim 25
Dependent Claim
31 words
The system of claim 18 wherein the controller further includes: a phase advance angle controller to vary a phase advance angle of the phase currents in the third mode of operation.
Claim 26
Dependent Claim
15 words
The system of claim 22 wherein the phase angle is varied in essentially 1° increments.
Claim 27
Dependent Claim
19 words
The system of claim 22 wherein the phase angle is varied up to a phase angle of essentially 90°.
Claim 28
Dependent Claim
56 words
The system of claim 18 wherein said controller comprises: a signal processor responsive to at least one of the signals indicative of the parameter of the motor and the command signal, and having a memory for storing signals including signals defining and executable algorithm for selecting the mode of operation and the producing the control signals.
Claim 29
Dependent Claim
201 words
A permanent magnet motor control system for an electric vehicle, comprising: a permanent magnet motor associated with the electric vehicle; a battery associated with the electric vehicle; a controller for selecting a mode of operation from a first mode of operation and a second mode of operation, the first and second modes of operation being constant torque modes, said controller producing control signals based on at least one of a signal indicative of a parameter of the motor and a command signal; and an inverter receptive to direct current signals from the battery for providing phase currents to the motor, said inverter, in response to the control signals, providing phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected and are substantially sinusoidal and substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected, wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value; and wherein said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 30
Dependent Claim
201 words
A permanent magnet motor control system for an electric vehicle, comprising: a permanent magnet motor associated with the electric vehicle; a battery associated with the electric vehicle; a controller for selecting a mode of operation from a first mode of operation and a second mode of operation, the first and second modes of operation being constant torque modes, said controller producing control signals based on at least one of a signal indicative of a parameter of the motor and a command signal; and an inverter receptive to direct current signals from the battery for providing phase currents to the motor, said inverter, in response to the control signals, providing phase currents which are substantially in phase with corresponding electromotive forces of the motor when the first mode of operation is selected and are substantially sinusoidal and substantially in phase with corresponding electromotive forces of the motor when the second mode of operation is selected, wherein the second mode of operation is selected from the first mode of operation when a load current exceeds a preset value; and wherein said permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 31
Dependent Claim
23 words
The system of claim 26 wherein the phase currents of said second mode of operation which are substantially sinusoidal comprise sinusoidal phase currents.
Claim 32
Dependent Claim
20 words
The system of claim 26 wherein the phase currents of said first mode of operation are substantially rectangular phase currents.
Claim 33
Dependent Claim
29 words
The system of claim 26 wherein the permanent magnet motor comprises a permanent magnet brushless direct current motor having a trapezoidal distribution of magnetic field in an airgap thereof.
Claim 34
Dependent Claim
35 words
The system of claim 26 wherein: the phase currents of the first mode of operation comprise essentially 120° phase currents; and the phase currents of the second mode of operation comprise essentially 180° phase currents.
Claim 35
Dependent Claim
31 words
The system of claim 26 wherein the controller further includes: a phase advance angle controller to vary a phase advance angle of the phase currents in a third mode of operation.
Claim 36
Dependent Claim
15 words
The system of claim 31 wherein the phase angle is varied in essentially 1° increments.
Claim 37
Dependent Claim
19 words
The system of claim 31 wherein the phase angle is varied up to a phase angle of essentially 90°.
Claim 38
Dependent Claim
25 words
The method of claim 1 wherein selecting the second mode of operation from the first mode of operation avoids substantially demagnetizing magnets on the motor.
Claim 39
Dependent Claim
25 words
The method of claim 9 wherein selecting the second mode of operation from the first mode of operation avoids substantially demagnetizing magnets on the motor.
Claim 40
Dependent Claim
25 words
The system of claim 18 wherein selecting the second mode of operation from the first mode of operation avoids substantially demagnetizing magnets on the motor.
Claim 41
Dependent Claim
25 words
The system of claim 26 wherein selecting the second mode of operation from the first mode of operation avoids substantially demagnetizing magnets on the motor.
References Cited (Backward Citations)
US4321518A
Cited
US4444285A
Cited
US4454458A
Cited
US4651066A
Cited
US4651069A
Cited
US4490661A
Cited
US4720663A
Cited
US4707650A
Cited
US4835448A
Cited
US4926099A
Cited
US5677605A
Cited
US4926104A
Cited
US5029263A
Cited
US5034668A
Cited
US5583411A
Cited
US5420492A
Cited
US5549172A
Cited
US5569995A
Cited
US5777447A
Cited
US5739664A
Cited
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