US5220259A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dc motor drive system and method
Assignee: Graco Inc
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Filing: 1991-10-03
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Granted: 1993-06-15
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Expires: 2011-10-03
Abstract
Abstract A DC motor drive system for providing an enhanced motor speed/torque relationship, where circuits modify the motor field winding control switching sequence to compensate for speed effects on motor torque output and to compensate on transient loading effects on motor torque output, and to compensate for rotor inertial effects caused by transient motor load changes.
Inventors
- 👤 Neal A. Werner
- 👤 Gary W. Box
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:09
CPC Classifications
H; H02; H02P; H02P7/00; H02P6/00; H02P6/06; F; F04; F04B; F04B49/00; F04B49/06; F04B49/065; H02P6/34; F04B2203/00; F04B2203/02; F04B2203/0207; F04B2203/0209
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
169 words
An apparatus for controlling the driver bus current in a DC motor drive system by selectively controlling the switching intervals of a plurality of inverter switches coupled to the motor field windings, comprising: means for manually selecting a set-point torque value defining the desired motor output torque; means for monitoring the instantaneous motor driver bus current and developing a motor driver bus current control signal therefrom; means for monitoring the motor rotor rotational speed and developing a motor rotor speed control signal therefrom; means for modifying said set-point torque value, responsive to said motor rotor speed control signal, to produce a modified set-point torque value; means for simulating motor winding phase current by utilizing said motor driver bus current and rotor speed control signals to generate a simulated motor phase current signal; means for utilizing said modified set-point torque value and said simulated motor phase current signal, and means for developing an inverter control signal therefrom; and means for turning off said inverter switches with said inverter control signal.
Claim 2
Independent Claim
169 words
An apparatus for controlling the driver bus current in a DC motor drive system by selectively controlling the switching intervals of a plurality of inverter switches coupled to the motor field windings, comprising: means for manually selecting a set-point torque value defining the desired motor output torque; means for monitoring the instantaneous motor driver bus current and developing a motor driver bus current control signal therefrom; means for monitoring the motor rotor rotational speed and developing a motor rotor speed control signal therefrom; means for modifying said set-point torque value, responsive to said motor rotor speed control signal, to produce a modified set-point torque value; means for simulating motor winding phase current by utilizing said motor driver bus current and rotor speed control signals to generate a simulated motor phase current signal; means for utilizing said modified set-point torque value and said simulated motor phase current signal, and means for developing an inverter control signal therefrom; and means for turning off said inverter switches with said inverter control signal.
Claim 3
Dependent Claim
46 words
The apparatus of claim 1, wherein said means for monitoring instantaneous motor driver bus current and developing a motor driver bus current control signal therefrom further comprises a current sensor and first circuit means for developing a signal I BUS representative or motor driver bus current.
Claim 4
Dependent Claim
32 words
The apparatus of claim 2, wherein said means for manually selecting a set-point torque value further comprises second circuit means for developing a signal I COM representative of said set-point torque value.
Claim 5
Dependent Claim
39 words
The apparatus of claim 3, wherein said means for monitoring motor rotor speed and developing a motor rotor speed control signal therefrom further comprises third circuit means for developing a signal I SPD representative of the motor rotor speed.
Claim 6
Dependent Claim
36 words
The apparatus of claim 4, wherein said means for modifying said set-point torque value further comprises fourth circuit means for developing a signal I MOD which is the sum of I COM and I SPD .
Claim 7
Dependent Claim
54 words
The apparatus of claim 5, wherein said means for monitoring the instantaneous motor driver bus current and developing a motor driver bus current control signal therefrom further comprises fifth circuit means coupled to receive said I BUS signal and for developing a signal I PEAK representative of the peak value of I BUS .
Claim 8
Dependent Claim
56 words
The apparatus of claim 6, wherein said means for monitoring the instantaneous motor driver bus current and developing a motor driver bus current control signal therefrom further comprises sixth circuit means coupled to receive said I PEAK signal and said I SPD signal, for developing a signal I PHASE representative of said motor winding phase current.
Claim 9
Dependent Claim
38 words
The apparatus of claim 7, wherein said means for utilizing said modified set-point torque value and said simulated motor phase current signal further comprises seventh circuit means for comparing said I PHASE signal with said I MOD signal.
Claim 10
Dependent Claim
105 words
The apparatus of claim 8, wherein said means for utilizing said modified set-point torque value and said simulated motor phase current signal further comprises eighth circuit means for comparing said I PHASE to said I MOD , and ninth circuit means for developing an error signal I ERROR if said I PHASE is greater than said I MOD , the magnitude of said I ERROR being proportional to the difference between said I PHASE and said I MOD ; and tenth circuit means for developing an error signal I ERROR equal to zero if said I PHASE is not greater than said I MOD .
Claim 11
Dependent Claim
59 words
The apparatus of claim 9, wherein said means for utilizing said modified set-point torque value and said simulated motor phase current signal further comprises eleventh circuit means coupled to receive said I MOD signal and said I ERROR signal, and for developing a signal I SET representative of the sum of said I MOD and said I ERROR .
Claim 12
Dependent Claim
49 words
The apparatus of claim 10, wherein said means for turning off said inverter switches further comprises twelfth circuit means for comparing said I BUS signal with said I SET signal, and for generating a turn-off signal to said inverter switches when said I BUS equals said I SET .
Claim 13
Dependent Claim
31 words
The apparatus of claim 1, further comprising means for calculating the rate of change of motor rotor speed, and means for comparing the calculated rate of change against a predetermined value.
Claim 14
Dependent Claim
39 words
The apparatus of claim 12, further comprising means for generating a BRK 1 and a BRK 2 signal when the means for comparing shows the calculated rate of change to be equal to or greater than the predetermined value.
Claim 15
Dependent Claim
28 words
The apparatus of claim 13, further comprising first means for receiving said BRK 1 signal and means for reversing the commutation sequence of said motor in response thereto.
Claim 16
Dependent Claim
36 words
The apparatus of claim 14, further comprising second means for receiving said BRK 2 signal and means responsive thereto for setting said simulated motor phase current signal equal to said motor driver bus current control signal.
Claim 17
Dependent Claim
31 words
The apparatus of claim 15, further comprising further means for changing said set-point torque value to a value equal to a constant multiplied by said motor rotor rotational speed control signal.
Claim 18
Dependent Claim
49 words
The apparatus of claim 16, wherein said means for modifying said set-point torque value, responsive to said motor rotor speed control signal, further comprises means for developing a modified signal I MOD equal to the sum of said motor rotor speed control signal and said changed set-point torque value.
Claim 19
Dependent Claim
28 words
The apparatus of claim 17, wherein said means for simulating phase current further comprises means for simulating a phase current equal to said instantaneous motor driver bus current.
Claim 20
Dependent Claim
66 words
The apparatus of claim 18, wherein said means for utilizing said modified set-point torque value and said simulated motor phase signal further comprises means for utilizing said I MOD signal and said instantaneous motor driver bus current, and said means for developing an inverter control signal comprises means for turning off said inverter switches when said I MOD signal equals said instantaneous motor driver bus current.
Claim 21
Dependent Claim
201 words
In a DC motor drive system having variable loading conditions and comprising semiconductor switches interposed between a direct current supply and the DC motor field windings, the improvement in controlling said switches to provide a constant motor torque output corresponding to a manually-set torque set-point value, comprising: a) means for monitoring the DC motor driver bus peak current and generating a first control signal (I PEAK ) responsive thereto; b) means for monitoring the DC motor rotor speed and generating a second control signal (I SPD ) responsive thereto; c) means for generating a third control signal (I MOD ) by additively combining said second control signal with said set-point value; d) means for generating a fourth control signal (I PHASE ) by linearly reducing said first control signal over time; e) means for comparing said third control signal and said fourth control signal, including means for generating an error signal if said fourth control signal exceeds said third control signal; f) means for generating a fifth control signal by additively combining said error signal and said third control signal; and g) means for shutting off said switches when said fifth control signal becomes equal to the motor field winding current.
Claim 22
Dependent Claim
201 words
In a DC motor drive system having variable loading conditions and comprising semiconductor switches interposed between a direct current supply and the DC motor field windings, the improvement in controlling said switches to provide a constant motor torque output corresponding to a manually-set torque set-point value, comprising: a) means for monitoring the DC motor driver bus peak current and generating a first control signal (I PEAK ) responsive thereto; b) means for monitoring the DC motor rotor speed and generating a second control signal (I SPD ) responsive thereto; c) means for generating a third control signal (I MOD ) by additively combining said second control signal with said set-point value; d) means for generating a fourth control signal (I PHASE ) by linearly reducing said first control signal over time; e) means for comparing said third control signal and said fourth control signal, including means for generating an error signal if said fourth control signal exceeds said third control signal; f) means for generating a fifth control signal by additively combining said error signal and said third control signal; and g) means for shutting off said switches when said fifth control signal becomes equal to the motor field winding current.
Claim 23
Independent Claim
177 words
A method for controlling a DC motor drive system to produce a constant output torque under variable loading conditions, responsive to a preselected set-point torque, by controlling the DC motor driver bus current I BUS , comprising the steps of: a) selecting a set-point current I COM corresonding to said preselected set-point torque; b) monitoring the instantaneous motor drive bus current I BUS ; c) monitoring the motor rotational speed and developing a current I SPD responsive thereto; d) modifying I COM in correspondence with I SPD to form I MOD =I COM +I SPD ; e) simulating the motor phase current I PHASE by linearly reducing the peak value of I BUS at a time rate corresponding to I SPD ; f) comparing I PHASE with I MOD and developing an error signal proportional to the difference (I PHASE -I MOD ); g) forming a new set-point signal I SET equal to the sum of I MOD plus said error signal; and h) turning off the current I BUS when I SET equals I BUS .
Claim 24
Independent Claim
177 words
A method for controlling a DC motor drive system to produce a constant output torque under variable loading conditions, responsive to a preselected set-point torque, by controlling the DC motor driver bus current I BUS , comprising the steps of: a) selecting a set-point current I COM corresonding to said preselected set-point torque; b) monitoring the instantaneous motor drive bus current I BUS ; c) monitoring the motor rotational speed and developing a current I SPD responsive thereto; d) modifying I COM in correspondence with I SPD to form I MOD =I COM +I SPD ; e) simulating the motor phase current I PHASE by linearly reducing the peak value of I BUS at a time rate corresponding to I SPD ; f) comparing I PHASE with I MOD and developing an error signal proportional to the difference (I PHASE -I MOD ); g) forming a new set-point signal I SET equal to the sum of I MOD plus said error signal; and h) turning off the current I BUS when I SET equals I BUS .
Claim 25
Dependent Claim
61 words
The method of claim 21, wherein the step of simulating the motor phase current I PHASE further comprises capturing the peak value I PEAK of I BUS , and linearly reducing I PEAK to form I PHASE according to the relation I PHASE =I PEAK (1-nt) where "n" is a constant value and "t" is the reciprocal of I SPD .
Claim 26
Dependent Claim
56 words
The method of claim 22, wherein the step of comparing I PHASE with I MOD further comprises developing a zero error signal I ERROR =0 if I PHASE is not greater than I MOD , and developing an error signal I ERROR =(I PHASE -I MOD )×10 if I PHASE is greater than I MOD .
Claim 27
Dependent Claim
28 words
The method of claim 23, wherein the step of turning off the current I BUS further comprises turning off inverter driver transistors in the DC motor drive system.
Claim 28
Independent Claim
231 words
A method for controlling a DC motor drive system under variable loading conditions, comprising the steps of: a) manually setting a set-point motor torque output value I COM ; b) monitoring the instantaneous motor driver bus current I BUS ; c) monitoring the motor rotational speed I SPD ; d) modifying the set-point value I COM in correspondence with increases in motor rotational speed I SPD , to form a modified set-point value I MOD ; e) capturing the peak value I PEAK of the motor driver bus current I BUS ; f) linearly reducing the captured peak value at a time rate corresponding to motor rotational speed to simulate a motor phase current I PHASE ; g) comparing the simulated motor phase current I PHASE with I MOD , and developing an error signal if the simulated motor phase current is greater than the modified set-point value, the magnitude of the error signal being substantially greater than the difference between the simulated motor phase current and the modified set-point value; h) adding the error signal to the I MOD to create a new signal I SET ; i) comparing the new signal I SET to the driver bus current I BUS ; and j) shutting off the driver bus drive current I BUS when the driver bus current signal I BUS becomes equal to the new signal I SET .
Claim 29
Independent Claim
231 words
A method for controlling a DC motor drive system under variable loading conditions, comprising the steps of: a) manually setting a set-point motor torque output value I COM ; b) monitoring the instantaneous motor driver bus current I BUS ; c) monitoring the motor rotational speed I SPD ; d) modifying the set-point value I COM in correspondence with increases in motor rotational speed I SPD , to form a modified set-point value I MOD ; e) capturing the peak value I PEAK of the motor driver bus current I BUS ; f) linearly reducing the captured peak value at a time rate corresponding to motor rotational speed to simulate a motor phase current I PHASE ; g) comparing the simulated motor phase current I PHASE with I MOD , and developing an error signal if the simulated motor phase current is greater than the modified set-point value, the magnitude of the error signal being substantially greater than the difference between the simulated motor phase current and the modified set-point value; h) adding the error signal to the I MOD to create a new signal I SET ; i) comparing the new signal I SET to the driver bus current I BUS ; and j) shutting off the driver bus drive current I BUS when the driver bus current signal I BUS becomes equal to the new signal I SET .
References Cited (Backward Citations)
US4628499A
Cited
US5034671A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-14 | 1996-12-14 | 1997-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-14 | 2000-12-14 | 2001-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-14 | 2004-12-14 | 2005-06-15 | $7700.00 | Window Closed / Lapsed |