US4401934A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive control system for line-commutated inverters
Assignee: National Aeronautics and Space Administration
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Filing: 1981-08-07
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Granted: 1983-08-30
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Expires: 2001-08-07
Abstract
Abstract A control system for a permanent-magnet motor (10) driven by a multiphase line-commutated inverter (12) is provided with integrators (24) for integrating the back EMF of each phase of the motor for use in generating system control signals for an inverter gate logic (30) using a sync and firing angle (α) control generator (26) connected to the outputs of the integrators. A precision full-wave rectifier (16) provides a speed control feedback signal to a phase-delay rectifier (14) via a gain and loop compensation circuit (20) and to the integrators for adaptive control of the attenuation of low frequencies by the integrators as a function of motor speed, whereby as the motor speed increases, the attenuation of low frequency components by the integrators is increased to offset the gain of the integrators to spurious low frequencies. While the attenuation may be a continuous linear function of speed, a switch (Q 1 ) is employed to provide a step change in attenuation at 40% of speed.
Inventors
- 👤 Carlisle R. Dolland
- 👤 David A. Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:06
CPC Classifications
H; H02; H02P; H02P27/00; H02P27/04; H02P27/06; H02P27/048; H02P27/047
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
87 words
In a control system for a permanent-magnet motor driven by a multiphase line-commutated inverter, said control system having means for integrating the back EMF of each phase of said motor for use in generating system control signals for said inverter, an improvement comprising means for generating a signal proportional to motor speed, and adaptive means responsive to said motor speed signal for increasing the attenuation of low frequencies in the back EMF of each phase of said motor by said integrating means as said motor speed increases.
Claim 2
Dependent Claim
87 words
In a control system for a permanent-magnet motor driven by a multiphase line-commutated inverter, said control system having means for integrating the back EMF of each phase of said motor for use in generating system control signals for said inverter, an improvement comprising means for generating a signal proportional to motor speed, and adaptive means responsive to said motor speed signal for increasing the attenuation of low frequencies in the back EMF of each phase of said motor by said integrating means as said motor speed increases.
Claim 3
Dependent Claim
62 words
An improvement as defined in claim 1 wherein said adaptive means is comprised of electronic switches and filter circuits at the input of said integrating means for selectively altering connections of said filter circuits to so alter filter configurations as to shift the corner frequency of said integrating means away from the jω axis thereof as the speed of the motor increases.
Claim 4
Dependent Claim
68 words
An improvement as defined in claim 2 wherein said filter circuits for each EMF signal are comprised of an operational amplifier with an integrating capacitor for each EMF signal and at least two high-pass filters, a first one permanently connected to couple said EMF signal to said operational amplifier for integration and a second one connected in parallel with said first one by one of said electronic switches.
Claim 5
Dependent Claim
118 words
In a control system for a permanent-magnet motor driven by a line-commutated inverter, a separate integrator having an adaptive high-pass filter for use in generating system control signals for said inverter from back EMF of said motor, and means for generating a signal proportional to motor speed, and means responsive to said signal for shifting the corner frequency of the high-pass filter of each integrator away from the jω axis as the speed of the motor increases, whereby the attenuation of low-frequency components in said back EMF by the integrators is increased as the motor speed increases to offset the gain of the integrators to spurious low frequencies, thereby assuring a desired minimum power factor at all speeds.
Claim 6
Dependent Claim
118 words
In a control system for a permanent-magnet motor driven by a line-commutated inverter, a separate integrator having an adaptive high-pass filter for use in generating system control signals for said inverter from back EMF of said motor, and means for generating a signal proportional to motor speed, and means responsive to said signal for shifting the corner frequency of the high-pass filter of each integrator away from the jω axis as the speed of the motor increases, whereby the attenuation of low-frequency components in said back EMF by the integrators is increased as the motor speed increases to offset the gain of the integrators to spurious low frequencies, thereby assuring a desired minimum power factor at all speeds.
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) | 1986-08-29 | 1987-02-28 | 1987-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-29 | 1991-02-28 | 1991-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-29 | 1995-02-28 | 1995-08-30 | $7700.00 | Window Closed / Lapsed |