US5345156A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control for high speed operation of brushless permanent magnet motor
Assignee: Whirlpool Corp
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Filing: 1993-12-30
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Granted: 1994-09-06
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Expires: 2013-12-30
Abstract
Abstract A method and apparatus for operating a brushless permanent magnetic motor at speeds where zero crossings of stator phase voltages becomes unavailable, wherein applications of stator currents to one stator phase is temporarily halted to allow current in the phase to reach zero, and the zero crossings of the internal motor voltage is detected as a surrogate for the zero crossings of the stator phase back EMF. A controller can react to the detected zero crossings as if the phase current was being applied.
Inventors
- 👤 Julio Cesar Moreira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:39
CPC Classifications
D; D06; D06F; D06F37/00; D06F37/30; D06F37/304; H; H02; H02P; H02P6/00; H02P6/06; H02P6/14; H02P6/16; H02P6/18; H02P6/182; H02P6/187; D06F2103/00; D06F2103/44; D06F2103/46; D06F2105/00; D06F2105/46; D06F58/00; D06F58/32; D06F58/34; F; F25; F25B; F25B2600/00; F25B2600/02; F25B2600/021; F25B2700/00; F25B2700/17; F25B2700/171; F25D; F25D2700/00; F25D2700/12; Y; Y02; Y02B; Y02B40/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
175 words
A method for controlling a brushless permanent magnet motor having stator windings connected in a star configuration which provides a stator neutral node and in which windings are induced back EMF fundamental and third harmonic components, and a rotor which rotates relative to the stator windings, the motor being driven by an inverter having electrical nodes, comprising the steps of: extracting a first signal in which the third harmonic component is dominant; filtering the first signal to generate a second signal which substantially contains only the third harmonic component; integrating the second signal to provide a third signal comprising the time integral of the second signal; communicating the third signal to a controller which controls operation of the inverter; at preselected intervals of operation of the motor, deliberately precluding application of current signals to one of the stator windings of the motor, sensing a voltage of the respective stator winding and generating a fourth signal with information about the back EMF experienced by the respective stator winding; and communicating the fourth signal to the controller.
Claim 2
Independent Claim
175 words
A method for controlling a brushless permanent magnet motor having stator windings connected in a star configuration which provides a stator neutral node and in which windings are induced back EMF fundamental and third harmonic components, and a rotor which rotates relative to the stator windings, the motor being driven by an inverter having electrical nodes, comprising the steps of: extracting a first signal in which the third harmonic component is dominant; filtering the first signal to generate a second signal which substantially contains only the third harmonic component; integrating the second signal to provide a third signal comprising the time integral of the second signal; communicating the third signal to a controller which controls operation of the inverter; at preselected intervals of operation of the motor, deliberately precluding application of current signals to one of the stator windings of the motor, sensing a voltage of the respective stator winding and generating a fourth signal with information about the back EMF experienced by the respective stator winding; and communicating the fourth signal to the controller.
Claim 3
Dependent Claim
25 words
The method of claim 1, wherein the first signal is extracted from across the stator neutral node and a negative power node of the inverter.
Claim 4
Dependent Claim
57 words
The method of claim 1, wherein a network of resistors connected in star configuration is coupled to the inverter so as to include an artificial neutral node separate and apart from, but in correspondence with, the stator neutral node, and the first signal is extracted from across the artificial neutral node and a node of the inverter.
Claim 5
Dependent Claim
25 words
The method of claim 3, wherein the first signal is extracted from across the artificial neutral node and a negative power node of the inverter.
Claim 6
Dependent Claim
30 words
The method of claim 3, wherein the first signal is extracted from across the artificial neutral node and an electrical node positioned electrically between the power nodes of the inverter.
Claim 7
Dependent Claim
20 words
The method of claim 1, comprising the further steps of measuring the speed of the motor during the preselected intervals.
Claim 8
Dependent Claim
48 words
The method of claim 6, comprising the steps of: comparing a plurality of motor speeds measured during a respective like plurality of preselected intervals; and adjusting application of currents to the stator windings by the inverter to operate the motor at the highest speed measured of those compared.
Claim 9
Independent Claim
198 words
A system for controlling a brushless permanent magnet motor having stator windings connected in a star configuration which provides a stator neutral node and in which windings are induced back EMF fundamental and third harmonic components, and a rotor which rotates relative to the stator windings, the motor being driven by an inverter having electrical nodes, comprising: means for extracting a first signal in which the third harmonic component is dominant; a filter for filtering the first signal to generate a second signal which substantially contains only the third harmonic component; an integrator unit for integrating the second signal to provide a third signal comprising the time integral of the second signal; a controller to which the third signal is communicated and which controls operation of the inverter, the controller being configured to deliberately preclude application of current signals to one of the stator windings of the motor during preselected intervals of operation of the motor; means for extracting a stator winding voltage of the respective stator winding during the preselected intervals, and to generate a fourth signal with information about the back EMF experienced by the respective stator winding, which fourth signal is communicated to the controller.
Claim 10
Independent Claim
198 words
A system for controlling a brushless permanent magnet motor having stator windings connected in a star configuration which provides a stator neutral node and in which windings are induced back EMF fundamental and third harmonic components, and a rotor which rotates relative to the stator windings, the motor being driven by an inverter having electrical nodes, comprising: means for extracting a first signal in which the third harmonic component is dominant; a filter for filtering the first signal to generate a second signal which substantially contains only the third harmonic component; an integrator unit for integrating the second signal to provide a third signal comprising the time integral of the second signal; a controller to which the third signal is communicated and which controls operation of the inverter, the controller being configured to deliberately preclude application of current signals to one of the stator windings of the motor during preselected intervals of operation of the motor; means for extracting a stator winding voltage of the respective stator winding during the preselected intervals, and to generate a fourth signal with information about the back EMF experienced by the respective stator winding, which fourth signal is communicated to the controller.
Claim 11
Dependent Claim
25 words
The system of claim 8, wherein the first signal is extracted from across the stator neutral node and a negative power node of the inverter.
Claim 12
Dependent Claim
59 words
The system of claim 8, further comprising a network of resistors connected in star configuration which is coupled to the inverter so as to include an artificial neutral node separate and apart from, but in correspondence with, the stator neutral node, and the first signal is extracted from across the artificial neutral node and a node of the inverter.
Claim 13
Dependent Claim
25 words
The system of claim 10, wherein the first signal is extracted from across the artificial neutral node and a negative power node of the inverter.
Claim 14
Dependent Claim
43 words
The system of claim 10, wherein an electrical node is provided electrically between power nodes of the inverter and the first signal is extracted from across the artificial neutral node and the electrical node positioned electrically between the power nodes of the inverter.
Claim 15
Dependent Claim
19 words
The system of claim 10, further comprising means for measuring the speed of the motor during the preselected intervals.
Claim 16
Dependent Claim
62 words
The system of claim 8, further comprising a zero crossing detection unit that detects zero crossings of the third and fourth signals and which generates fifth and sixth signals with information about the zero crossings of the third and fourth signals, respectively, the controller being configured to synchronize application of stator currents with motor operation based on the fifth and sixth signals.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-05 | 1998-03-07 | 1998-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-05 | 2002-03-07 | 2002-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-05 | 2006-03-07 | 2006-09-06 | $7700.00 | Window Closed / Lapsed |