US5350984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for starting a brushless DC motor
Assignee: STMicroelectronics lnc USA
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Filing: 1993-03-12
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Granted: 1994-09-27
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Expires: 2013-03-12
Abstract
Abstract A method for aligning a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, sets of the coils being selectively energizable by a power source connected to the motor, includes steps of energizing a first set of at least one coil of the at least two coils; generating a signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the first set was energized; and when the signal indicates that the rotor has not been rotated at a rotary speed greater than the predetermined rotary speed, switching the connection between the power source and the motor and energizing a second set of at least one coil of the at least two coils. A device for controlling an alignment of a rotor of a brushless and sensorless DC motor includes a circuit for energizing a first set of at least one coil; a circuit for generating a signal indicating whether the rotor has been rotated due the first set having been energized; and a circuit for energizing a second set of at least one coil when the signal indicates the rotor has not been rotated.
Inventors
- 👤 Francesco Carobolante
- 👤 Ermanno Pace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:00
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/20
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
120 words
A method for aligning a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, the coils being selectively energizable by a power source connected to the motor, the method comprising steps of: energizing a first coil of the at least two coils; generating a signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the first coil was energized; and when the signal indicates that the rotor has not been rotated at the rotary speed greater than the predetermined rotary speed, commutating the connection between the power source and the motor and energizing a second coil of the at least two coils.
Claim 2
Independent Claim
120 words
A method for aligning a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, the coils being selectively energizable by a power source connected to the motor, the method comprising steps of: energizing a first coil of the at least two coils; generating a signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the first coil was energized; and when the signal indicates that the rotor has not been rotated at the rotary speed greater than the predetermined rotary speed, commutating the connection between the power source and the motor and energizing a second coil of the at least two coils.
Claim 3
Dependent Claim
31 words
The method of claim 1, wherein: the step of energizing the first coil leaves the second coil unenergized; and the step of energizing the second coil leaves the first coil unenergized.
Claim 4
Dependent Claim
30 words
The method of claim 1, wherein the step of generating a signal includes sensing a back EMF signal from at least one unenergized coil of the at least two coils.
Claim 5
Dependent Claim
36 words
The method of claim 3, wherein the step of generating a signal further includes detecting a condition when the back EMF signal is one of greater than a plus threshold and less than a minus threshold.
Claim 6
Dependent Claim
33 words
The method of claim 4, wherein the step of generating a signal further includes producing the signal when the step of detecting detects the condition at any time within a predetermined settling time.
Claim 7
Dependent Claim
39 words
The method of claim 1, wherein: the step of energizing the first coil energizes the first coil for a first predetermined time; and the step of energizing the second coil energizes the second coil for a second predetermined time.
Claim 8
Dependent Claim
58 words
The method of claim 1, wherein the step of energizing the first coil energizes the first coil for a first predetermined time, the method aligning the rotor in a predetermined settling time when the signal indicates that the rotor has been rotated at the rotary speed greater than the predetermined rotary speed while the first coil was energized.
Claim 9
Dependent Claim
72 words
The method of claim 7, wherein the method energizes the second coil for a second predetermined time when the signal indicates that the rotor has not been rotated at the rotary speed greater than the predetermined rotary speed while the first coil was energized, and generating a second signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the second coil was energized.
Claim 10
Dependent Claim
32 words
The method of claim 1, wherein the step of generating a signal includes connecting the second coil to a sense circuit to generate the signal while the first coil is being energized.
Claim 11
Independent Claim
97 words
A method for controlling an alignment of a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, subsets of the coils being selectively energizable by a power source connected to the motor, the method comprising the steps of: energizing a first subset of the at least two coils; generating a signal indicating whether the rotor has been rotated due to the first subset having been energized; and when the signal indicates that the rotor has not been rotated, energizing a second subset of the at least two coils.
Claim 12
Independent Claim
97 words
A method for controlling an alignment of a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, subsets of the coils being selectively energizable by a power source connected to the motor, the method comprising the steps of: energizing a first subset of the at least two coils; generating a signal indicating whether the rotor has been rotated due to the first subset having been energized; and when the signal indicates that the rotor has not been rotated, energizing a second subset of the at least two coils.
Claim 13
Independent Claim
143 words
A device for aligning a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, sets of at least one coil being selectively energizable by a power source connected to the motor, the device comprising: a first circuit for energizing a first set of at least one coil of the at least two coils; a comparator circuit for generating a signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the first set was energized; and energizing means for commutating the connection between the power source and the motor and energizing a second set of at least one coil of the at least two coils when the signal indicates that the rotor has not been rotated at the rotary speed greater than the predetermined rotary speed.
Claim 14
Independent Claim
143 words
A device for aligning a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, sets of at least one coil being selectively energizable by a power source connected to the motor, the device comprising: a first circuit for energizing a first set of at least one coil of the at least two coils; a comparator circuit for generating a signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the first set was energized; and energizing means for commutating the connection between the power source and the motor and energizing a second set of at least one coil of the at least two coils when the signal indicates that the rotor has not been rotated at the rotary speed greater than the predetermined rotary speed.
Claim 15
Dependent Claim
33 words
The device of claim 11, wherein: the first circuit energizes the first set while leaving the second set unenergized; and the energizing means energizes the second set while leaving the first set unenergized.
Claim 16
Dependent Claim
30 words
The device of claim 11, wherein the comparator circuit includes a circuit for sensing a back EMF signal from at least one unenergized coil of the at least two coils.
Claim 17
Dependent Claim
36 words
The device of claim 13, wherein the comparator circuit further includes a circuit for detecting a condition when the back EMF signal is one of greater than a plus threshold and less than a minus threshold.
Claim 18
Dependent Claim
33 words
The device of claim 14, wherein the comparator circuit further includes a circuit for producing the signal when the circuit for detecting detects the condition at any time within a predetermined energizing time.
Claim 19
Dependent Claim
31 words
The device of claim 11, wherein: the first circuit energizes the first set for a predetermined settling time; and the energizing means energizes the second set for a second predetermined time.
Claim 20
Dependent Claim
57 words
The device of claim 11, wherein the first circuit energizes the first set for a predetermined settling time, the device controlling the rotor to be aligned in a predetermined settling time when the signal indicates that the rotor has been rotated at the rotary speed greater than the predetermined rotary speed while the first set was energized.
Claim 21
Dependent Claim
89 words
The device of claim 17, wherein the energizing means comprises: a second circuit for energizing the second set of at least one coil of the at least two coils when the signal indicates that the rotor has not been rotated at the rotary speed greater than the predetermined rotary speed while the first set was energized, and a second comparator circuit for generating a second signal indicating whether the rotor has been rotated at a rotary speed greater than a predetermined rotary speed while the second set was energized.
Claim 22
Dependent Claim
34 words
The method of claim 11, wherein the comparator circuit includes a sense circuit selectively connectable to a set of at least one unenergized coil to generate the signal while the first set is energized.
Claim 23
Independent Claim
115 words
A device for controlling an alignment of a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, sets of the coils being selectively energizable by a power source connected to the motor, the device comprising: first energizing means for energizing a first set of at least one coil of the at least two coils; generating means for generating a signal indicating whether the rotor has been rotated due to the first set having been energized; and second energizing means for energizing a second set of at least one coil of the at least two coils when the signal indicates that the rotor has not been rotated.
Claim 24
Independent Claim
115 words
A device for controlling an alignment of a rotor of a brushless and sensorless DC motor, the motor having a stator with at least two coils, sets of the coils being selectively energizable by a power source connected to the motor, the device comprising: first energizing means for energizing a first set of at least one coil of the at least two coils; generating means for generating a signal indicating whether the rotor has been rotated due to the first set having been energized; and second energizing means for energizing a second set of at least one coil of the at least two coils when the signal indicates that the rotor has not been rotated.
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) | 1997-09-26 | 1998-03-28 | 1998-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-26 | 2002-03-28 | 2002-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-26 | 2006-03-28 | 2006-09-27 | $7700.00 | Window Closed / Lapsed |