Patent US5854877A successfully refreshed from Google Patents.
US5854877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Economical wide range speed control system
Assignee: Quantum Corp
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Filing: 1996-10-16
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Granted: 1998-12-29
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Expires: 2016-10-16
Abstract
Abstract A speed control system is disclosed wherein a brushless DC motor and a magneto resistive encoder are able to rotate a motor at arbitrarily low speeds. The motor is able to rotate at low speeds by having a filtered signal generated by an encoder applied to its inputs. The encoder is coupled to a series of filters which remove DC level and harmonic distortions from the resulting encoder signal. These filtered signals are then applied to the motor to control motor rotation speed.
Inventors
- 👤 Martyn A. Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:42
CPC Classifications
H; H02; H02P; H02P5/00; H02P6/00; H02P6/10; H02P23/00; H02P23/16; H02P23/18; H02P23/186; H02P6/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
155 words
A speed control system, comprising: a signal source for producing a modulation frequency signal; an encoder having a moveable member operatively connected to a device whose speed is to be controlled, said encoder coupled to said signal source, said encoder including means for converting said modulation frequency signal into a phase variable signal having a phase which is varied as a function of the position of said moveable member; a reference frequency signal generator coupled to said modulation frequency signal source for generating a variable reference frequency signal; a comparator operatively connected to said modulation frequency signal and said reference frequency signal for generating an error signal; and a plurality of filters in communication with said encoder, each of said plurality of filters including a notch filter operative to remove DC and frequency based distortions from said error signal, said plurality of filters providing a control signal used to control said device at low speeds.
Claim 2
Dependent Claim
155 words
A speed control system, comprising: a signal source for producing a modulation frequency signal; an encoder having a moveable member operatively connected to a device whose speed is to be controlled, said encoder coupled to said signal source, said encoder including means for converting said modulation frequency signal into a phase variable signal having a phase which is varied as a function of the position of said moveable member; a reference frequency signal generator coupled to said modulation frequency signal source for generating a variable reference frequency signal; a comparator operatively connected to said modulation frequency signal and said reference frequency signal for generating an error signal; and a plurality of filters in communication with said encoder, each of said plurality of filters including a notch filter operative to remove DC and frequency based distortions from said error signal, said plurality of filters providing a control signal used to control said device at low speeds.
Claim 3
Dependent Claim
19 words
The system of claim 1, further including a digital filter operative to remove viscous distortions from said error signal.
Claim 4
Dependent Claim
18 words
The system of claim 1, wherein said modulation frequency signal and said variable reference frequency signal are different.
Claim 5
Dependent Claim
16 words
The system of claim 1, wherein each of said plurality of filters is a digital filter.
Claim 6
Dependent Claim
20 words
The system of claim 1, wherein: said filters further include either a high pass filter or a band pass filter.
Claim 7
Dependent Claim
21 words
The system of claim 5, wherein said high pass filter or said band pass filter is coupled to said notch filter.
Claim 8
Dependent Claim
165 words
A speed control system, comprising: a modulation signal source for producing a modulation frequency signal; a motor having a shaft, said motor being coupled to said modulation signal source; an encoder coupled to said motor, said encoder generating a phase variable signal having a phase which is varied as a function of said motor shaft position; a reference signal generator coupled to said modulation signal source, said reference signal generator operative to produce a variable reference frequency signal which may differ in frequency or phase from said modulation frequency signal; a comparator coupled to said modulation signal source and said reference signal generator, said comparator generating an error signal based on any difference between said modulation signal and said reference signal; and a series of digital filters, coupled to said comparator, each respective one of said series of filters including a neural network for removing frequency distortions present in said error signal and providing a central signal operative to control said motor at low speeds.
Claim 9
Dependent Claim
165 words
A speed control system, comprising: a modulation signal source for producing a modulation frequency signal; a motor having a shaft, said motor being coupled to said modulation signal source; an encoder coupled to said motor, said encoder generating a phase variable signal having a phase which is varied as a function of said motor shaft position; a reference signal generator coupled to said modulation signal source, said reference signal generator operative to produce a variable reference frequency signal which may differ in frequency or phase from said modulation frequency signal; a comparator coupled to said modulation signal source and said reference signal generator, said comparator generating an error signal based on any difference between said modulation signal and said reference signal; and a series of digital filters, coupled to said comparator, each respective one of said series of filters including a neural network for removing frequency distortions present in said error signal and providing a central signal operative to control said motor at low speeds.
Claim 10
Dependent Claim
22 words
The system of claim 7, wherein: said filter includes at least one high pass filter or at least one band pass filter.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-12-28 | 2002-06-29 | 2002-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-28 | 2006-06-29 | 2006-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-28 | 2010-06-29 | 2010-12-29 | $7700.00 | Window Closed / Lapsed |