US3899725A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Braking effort control
Assignee: General Electric Co
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Filing: 1974-02-25
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Granted: 1975-08-12
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Expires: 1994-02-25
Abstract
Abstract During the electric braking of an inverter powered propulsion vehicle, it is desirable that the constant torque performance characteristics be extended to a speed beyond that for which pulse width modulation can be effectively used to control voltage. This extension is accomplished by compensating the current command signal, and thus the motor current, by an amount proportional to the speed of the vehicle and inversely proportional to the inverter d-c voltage during periods of operation above the pulse width modulated speeds. A comparator is provided to select the higher of either the uncompensated or compensated current commands, thereby allowing the current command signal to be unaffected during pulse width modulation modes and to be automatically compensated at speeds thereabove.
Inventors
- 👤 Allan B Plunkett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:42
CPC Classifications
H; H02; H02P; H02P23/00; H02P23/08; B; B60; B60L; B60L7/00; B60L7/22; H02P23/06; H02P23/07; H02P27/00; H02P27/04; H02P27/047; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/64
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
142 words
An improved control circuit for an inverter which is suitable for interconnecting a d-c power source and an a-c motor load, the a-c motor being adapted to deliver power to the inverter during periods of electrical braking and the inverter being operative in a square wave mode when the speed of said motor is above a predetermined value, wherein the improvement comprises: a. means for generating a current command signal representative of the desired motor current; b. means for modulating said current command signal in response both to the motor speed and to changes in the motor voltage; and c. means responsive to the modulated command signal for controlling the operation of said inverter so as to control the motor current during periods of electrical braking and to maintain a constant torque output whenever the motor speed is above said predetermined value.
Claim 2
Dependent Claim
142 words
An improved control circuit for an inverter which is suitable for interconnecting a d-c power source and an a-c motor load, the a-c motor being adapted to deliver power to the inverter during periods of electrical braking and the inverter being operative in a square wave mode when the speed of said motor is above a predetermined value, wherein the improvement comprises: a. means for generating a current command signal representative of the desired motor current; b. means for modulating said current command signal in response both to the motor speed and to changes in the motor voltage; and c. means responsive to the modulated command signal for controlling the operation of said inverter so as to control the motor current during periods of electrical braking and to maintain a constant torque output whenever the motor speed is above said predetermined value.
Claim 3
Dependent Claim
25 words
An improved inverter control circuit as set forth in claim 1 wherein said current command signal is increased as the square root of motor speed.
Claim 4
Dependent Claim
131 words
An improved control circuit for an inverter which is suitable for interconnecting a d-c power source and an a-c motor load, the a-c motor being adapted to deliver power to the inverter during periods of electrical braking, wherein the improvement comprises: a. means for generating a current command signal representative of the desired motor current; b. means for compensating said current command signal by a factor proportional to the motor stator frequency and inversely proportional to the motor a-c voltage; c. means for deriving a modulated command signal comprising the higher of said current command signal and the compensated signal; and d. means responsive to said modulated command signal for controlling the operation of said inverter so as to control the current output of said motor during periods of electrical braking.
Claim 5
Dependent Claim
131 words
An improved control circuit for an inverter which is suitable for interconnecting a d-c power source and an a-c motor load, the a-c motor being adapted to deliver power to the inverter during periods of electrical braking, wherein the improvement comprises: a. means for generating a current command signal representative of the desired motor current; b. means for compensating said current command signal by a factor proportional to the motor stator frequency and inversely proportional to the motor a-c voltage; c. means for deriving a modulated command signal comprising the higher of said current command signal and the compensated signal; and d. means responsive to said modulated command signal for controlling the operation of said inverter so as to control the current output of said motor during periods of electrical braking.
Claim 6
Dependent Claim
32 words
An improved inverter control circuit as set forth in claim 3 wherein said compensating means receives an input signal representative of the d-c inverter voltage and proportional to the motor a-c voltage.
Claim 7
Dependent Claim
31 words
An improved inverter control circuit as set forth in claim 3 wherein said compensating means receives an input signal representative of the motor speed and proportional to the motor stator frequency.
Claim 8
Dependent Claim
46 words
An improved inverter control circuit as set forth in claim 3 wherein said inverter is of the pulse width modulated type and further wherein said compensated signal is higher than said command signal only when said inverter is operating in a square wave mode of operation.
Claim 9
Dependent Claim
30 words
An improved control circuit as set forth in claim 3 wherein said modulated command signal deriving means comprises a pair of parallel input diodes connected to a common output terminal.
Claim 10
Dependent Claim
94 words
An improved torque control circuit of the type having an a-c motor, a d-c power source, an inverter and an inverter control circuit responsive to a current command signal representative of the desired motor stator current, wherein the improvement comprises: a. means for generating a tractive effort command signal; b. means for compensating said command signal by a factor proportional to the motor stator frequency and inversely proportional to the motor a-c voltage; c. means for selecting the higher of said command signal and said compensating signal for use as the current command signal.
Claim 11
Dependent Claim
94 words
An improved torque control circuit of the type having an a-c motor, a d-c power source, an inverter and an inverter control circuit responsive to a current command signal representative of the desired motor stator current, wherein the improvement comprises: a. means for generating a tractive effort command signal; b. means for compensating said command signal by a factor proportional to the motor stator frequency and inversely proportional to the motor a-c voltage; c. means for selecting the higher of said command signal and said compensating signal for use as the current command signal.
Claim 12
Dependent Claim
49 words
An improved control circuit as set forth in claim 8 wherein said inverter operates in a square wave mode above a first predetermined motor speed and further wherein said Current command signal is increased to maintain a constant torque output for motor speeds above said first predetermined motor speed.
Claim 13
Dependent Claim
24 words
An improved control circuit as set forth in claim 9 wherein said current command signal is increased as the square root of motor speed.
Claim 14
Dependent Claim
31 words
An improved control circuit as set forth in claim 8 wherein said compensating means receives an input signal representative of the d-c inverter voltage and proportional to the motor a-c voltage.
Claim 15
Dependent Claim
30 words
An improved control circuit as set forth in claim 8 wherein said compensating means receives an input signal representative of the rotor frequency and proportional to the motor stator frequency.
Claim 16
Dependent Claim
45 words
An improved control circuit as set forth in claim 8 wherein said inverter is of the pulse width modulated type and further wherein said compensated signal is higher than said command signal only when said inverter is operating in the square wave mode of operation.
Claim 17
Dependent Claim
27 words
an improved control circuit as set forth in claim 8 wherein said selecting means comprises a pair of parallel input diodes connected to a common output terminal.
Claim 18
Dependent Claim
136 words
An improved power circuit of the type having an inverter for connection to a d-c power source and an a-c motor, the a-c motor being adapted to deliver power to the inverter during periods of electrical braking, wherein the improvement comprises: a. means for generating a braking effort command signal representative of the desired braking torque to be applied by the motor; b. means for compensating said command signal by a factor proportional to the motor stator frequency and inversely proportional to the motor a-c voltage; c. means for selecting the higher of said command signal and said compensated signal to obtain a current command signal, representative of the desired motor current; and d. an inverter control circuit responsive to said current command signal to control the inverter and thus the torque output of the motor.
Claim 19
Dependent Claim
136 words
An improved power circuit of the type having an inverter for connection to a d-c power source and an a-c motor, the a-c motor being adapted to deliver power to the inverter during periods of electrical braking, wherein the improvement comprises: a. means for generating a braking effort command signal representative of the desired braking torque to be applied by the motor; b. means for compensating said command signal by a factor proportional to the motor stator frequency and inversely proportional to the motor a-c voltage; c. means for selecting the higher of said command signal and said compensated signal to obtain a current command signal, representative of the desired motor current; and d. an inverter control circuit responsive to said current command signal to control the inverter and thus the torque output of the motor.
Claim 20
Dependent Claim
38 words
An improved power circuit as set forth in claim 15 wherein the motor torque output is maintained as a constant value up to a predetermined speed by modulation of said current command signal and thus the motor current.
Claim 21
Dependent Claim
24 words
An improved power circuit as set forth in claim 16 wherein said current command signal is increased as the square root of motor speed.
Claim 22
Dependent Claim
29 words
An improved power circuit as set forth in claim 15 wherein said compensating means receives an input signal representative of the rotor frequency and proportional to the stator frequency.
Claim 23
Dependent Claim
31 words
An improved power circuit as set forth in claim 15 wherein said compensating means receives an input signal representative of the d-c inverter voltage and proportional to the motor a-c voltage.
Claim 24
Dependent Claim
60 words
An improved control circuit as set forth in claim 15 wherein said inverter is operated in a pulse width modulated mode up to a first predetermined motor speed and in a square wave mode thereafter, and further wherein said compensated signal is higher than said command signal only when the inverter is operating in the square wave mode of operation.
Claim 25
Dependent Claim
27 words
An improved power circuit as set forth in claim 15 wherein said selecting means comprises a pair of parallel input diodes connected to a common output terminal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |