Patent US4092572A successfully refreshed from Google Patents.
US4092572A
Expired / Lapsed
US
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Brushless D.C. motor driving system
Assignee: Pioneer Corp
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Filing: 1976-09-02
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Granted: 1978-05-30
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Expires: 1996-09-02
Abstract
Abstract A stator winding drive circuit for a brushless d.c. motor having a permanent magnet rotor and a plurality of stator poles unequal to the number of rotor poles. Hall elements sense the rotor position, but due to the unequal number of rotor and stator poles, if the amplified Hall element outputs are used to directly drive the stator windings some drive signal overlap will exist resulting in torque ripple. Therefore, the true and reciprocal Hall element outputs are applied to a resistive addition network to produce staircase waveforms, portions of which have the desired sequential timings and non-overlapping electrical durations. These waveforms are applied to threshold switching circuits triggered by such desired portions, and the switching circuit outputs feed the stator windings.
Inventors
- 👤 Motomu Murata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:22
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06; H02K29/08; H02P; H02P6/00; H02P6/14; H02P6/16
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
197 words
In a brushlesss direct current motor including a permanent magnet rotor having a plurality of poles, an electromagnet stator having a plurality of poles unequal to the number of rotor poles, and a plurality of angular rotor position sensing means spaced around the periphery of the stator and producing overlapping, phase displaced, rectangular waveforms, and reciprocal waveforms thereof, each waveform having an on-time duration or flow angle of 180 electrical ° with respect to the rotor, an improved stator winding drive circuit comprising: (a) a resistive addition network responsive to the sensing means waveforms for producing a plurality of staircase signals, the upper portions of which have sequential, consecutive, non-overlapping flow angles, (b) a plurality of stator windings, and (c) a threshold switching circuit responsive to the staircase signals and conductive only during the upper portions thereof for supplying the stator windings with sequential, consecutive, non-overlapping drive currents, whereby the motor efficiency is improved and torque ripple is reduced, wherein the addition network comprises a plurality of series connected, equal valued resistor pairs, two sensing means waveforms are coupled to the ends of each pair, and a staircase signal is taken from the junction of each pair.
Claim 2
Dependent Claim
197 words
In a brushlesss direct current motor including a permanent magnet rotor having a plurality of poles, an electromagnet stator having a plurality of poles unequal to the number of rotor poles, and a plurality of angular rotor position sensing means spaced around the periphery of the stator and producing overlapping, phase displaced, rectangular waveforms, and reciprocal waveforms thereof, each waveform having an on-time duration or flow angle of 180 electrical ° with respect to the rotor, an improved stator winding drive circuit comprising: (a) a resistive addition network responsive to the sensing means waveforms for producing a plurality of staircase signals, the upper portions of which have sequential, consecutive, non-overlapping flow angles, (b) a plurality of stator windings, and (c) a threshold switching circuit responsive to the staircase signals and conductive only during the upper portions thereof for supplying the stator windings with sequential, consecutive, non-overlapping drive currents, whereby the motor efficiency is improved and torque ripple is reduced, wherein the addition network comprises a plurality of series connected, equal valued resistor pairs, two sensing means waveforms are coupled to the ends of each pair, and a staircase signal is taken from the junction of each pair.
Claim 3
Dependent Claim
67 words
A stator winding drive circuit as defined in claim 1 wherein the threshold switching circuit comprises a plurality of transistor pairs, each pair comprising a first, threshold switching transistor having its base terminal connected to a staircase signal and its collector terminal connected to the base terminal of a second, drive transistor, and wherein the collector terminal of each drive transistor is connected to a stator winding.
Claim 4
Dependent Claim
34 words
A stator winding drive circuit as defined in claim 1 wherein each rotor position sensing means comprises a Hall element having two output terminals respectively coupled to the input terminals of a differential amplifier.
Claim 5
Dependent Claim
58 words
A stator winding drive circuit as defined in claim 1 wherein the rotor has six poles, the stator has nine poles, each stator winding comprises three series connected individual windings, there are three rotor position sensing means, and the upper portion of each staircase signal has a flow angle of 120 electrical ° with respect to the rotor.
References Cited (Backward Citations)
US4005347A
Cited
US4027212A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-29 | 1981-11-28 | 1982-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-29 | 1985-11-28 | 1986-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-29 | 1989-11-28 | 1990-05-30 | $7700.00 | Window Closed / Lapsed |