EP0049947B1
Expired / Lapsed
EP
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Motor control system
Assignee: 3M Co
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Filing: 1981-09-09
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Granted: 1985-11-21
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Expires: 2001-09-09
Abstract
No abstract record available.
Inventors
- 👤 Martyn A. Lewis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 18:46
CPC Classifications
G; G11; G11B; G11B19/00; G11B19/20; H; H02; H02P; H02P6/00; H02P6/08; H02P6/085
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
308 words
A motor control system for an electric motor (10) of the type having a rotor and a plurality of windings (28), having electronic commutation (30) for said plurality of windings (28), and having a linear speed control feedback loop for said windings (28) utilizing a velocity feedback sensor, said motor control system adapted to control said electric motor (10) characterized by having a current sensor (18, 20) coupled to said plurality of said windings (28) for producing a current feedback signal (22) indicative of the amount of the current flowing through said electric motor (10); a comparator (14) coupled in said linear speed control feedback loop and coupled to said current feedback signal (22) of said current sensor (18, 20) for providing a comparison output responsive to the result of a comparison between said linear speed control feedback loop and said current feedback signal (22), said comparison output indicative of the error in the desired position of said rotor in said electric motor (10) and of said current feedback signals (22); a transistor circuit (16) coupled to said comparison output, said transistor circuit (16) biased and capable of operating in both on and off states and operating therebetween in a linear mode; an inductor (24) coupled between said output of said transistor circuit (16) and said electronic commutation (30); and a positive feedback amplifier (26) coupled to said current sensor (18, 20) operative when said current feedback signal (22) exceeds a predetermined value to promote rapid changes in said current feedback signal (22); said transistor circuit (16) providing linear closed loop speed control feedback to said electronic commutation (30) when said current feedback signal (22) does not exceed said predetermined value and said transistor circuit (16) providing an oscillating pulse width modulation control of said electronic commutation (30) when said current feedback signal (22) exceeds said predetermined value.
Claim 2
Dependent Claim
308 words
A motor control system for an electric motor (10) of the type having a rotor and a plurality of windings (28), having electronic commutation (30) for said plurality of windings (28), and having a linear speed control feedback loop for said windings (28) utilizing a velocity feedback sensor, said motor control system adapted to control said electric motor (10) characterized by having a current sensor (18, 20) coupled to said plurality of said windings (28) for producing a current feedback signal (22) indicative of the amount of the current flowing through said electric motor (10); a comparator (14) coupled in said linear speed control feedback loop and coupled to said current feedback signal (22) of said current sensor (18, 20) for providing a comparison output responsive to the result of a comparison between said linear speed control feedback loop and said current feedback signal (22), said comparison output indicative of the error in the desired position of said rotor in said electric motor (10) and of said current feedback signals (22); a transistor circuit (16) coupled to said comparison output, said transistor circuit (16) biased and capable of operating in both on and off states and operating therebetween in a linear mode; an inductor (24) coupled between said output of said transistor circuit (16) and said electronic commutation (30); and a positive feedback amplifier (26) coupled to said current sensor (18, 20) operative when said current feedback signal (22) exceeds a predetermined value to promote rapid changes in said current feedback signal (22); said transistor circuit (16) providing linear closed loop speed control feedback to said electronic commutation (30) when said current feedback signal (22) does not exceed said predetermined value and said transistor circuit (16) providing an oscillating pulse width modulation control of said electronic commutation (30) when said current feedback signal (22) exceeds said predetermined value.
Claim 3
Dependent Claim
26 words
A motor control system as in claim 1 characterized by said oscillating pulse width modulation control being provided by the oscillation of said transistor circuit (16).
Claim 4
Dependent Claim
36 words
A motor control system as in claim 2 further characterized by a driver (310) coupled between said comparator (14) and said transistor circuit (16) to provide said transistor circuit with the amount of drive current required.
Claim 5
Dependent Claim
30 words
A motor control system as in claim 3 further characterized in that said transistor circuit (16) has a first transistor (316) and wherein said driver is a drive transistor (310).
Claim 6
Dependent Claim
89 words
A motor control system as in claim 1 further characterized in that said current sensor (18, 20) has a current resistor (18) coupled to said electronic commutation (30) such that the amount of current flowing through said current resistor (18) is responsive to the amount of current flowing through said electronic commutation (30); an operational amplifier (230) having two inputs and an output, said two inputs coupled across said current resistor (18); and a feedback resistor (230) coupled between said output of said operational amplifier (230) and said comparator.
Claim 7
Dependent Claim
20 words
A motor control system as in claim 5 further characterized in that said operational amplifier (230) operates in subtractive mode.
Claim 8
Dependent Claim
64 words
A motor control system as in claim 1 further characterized in that said comparator (14) has an operational amplifier (302) having two inputs and an output, one of said two inputs being coupled to said current sensor (18, 20) and the other of said two inputs being operatively coupled to a servo loop compensator (40), wherein said operational amplifier (302) operates in comparative mode.
Claim 9
Dependent Claim
43 words
A motor control system as in claim 7 further characterized in that said comparator (14) further has a compensation resistor (304) and a compensation capacitor (306) coupled between said one of said two inputs and said output to provide closed loop current compensation.
Claim 10
Dependent Claim
74 words
A motor control system as in claim 1 further characterized in that said transistor circuit (16) has a switching transistor (316) having a base, a collector and an emitter, said base coupled to said comparator (14) and to a biased circuit (318), said emitter being coupled to an emitter resistor (320) and said collector being coupled to said inductor (24) and to the cathode of a diode (324) whose anode is coupled to ground.
Claim 11
Dependent Claim
26 words
A motor control system as in claim 9, said transistor circuit (16) is further characterized by a capacitor (326) coupled between said collector and said base.
Claim 12
Dependent Claim
152 words
A motor control system as in claim 10 further characterized in that said current sensor (18, 20) is current resistor (18) and a subtractive operational amplifier (230) and characterized by said positive feedback amplifier (26) having a feedback operational amplifier (246) having two inputs and an output, one of said two inputs being coupled to said output of said subtractive operational amplifier (230) and the other of said two inputs being coupled to a steady voltage; a diode (256) having a cathode and an anode, said cathode being coupled to said output of said feedback operational amplifier (246); a feedback resistor (258) coupled between said anode and one of said two inputs of said subtractive operational amplifier (230); and a feedback capacitor (254) coupled between said output of said feedback operational amplifier (246) and said comparator (14); whereby positive feedback is introduced to the input side of said current sensor (18, 20).
Claim 13
Dependent Claim
30 words
Use of a motor control system as in claim 1 to control said electric motor (10) which controls the rotation of a record media for the recording of signals thereon.
Claim 14
Dependent Claim
25 words
Use of a motor control system as in claim 12 further characterized in that said record media is a medium having a relatively high inertia.
Claim 15
Dependent Claim
21 words
Use of a motor control system as in claim 12 further characterized in that said record media is a disc platter.
References Cited (Backward Citations)
No citation records indexed.
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