Patent US3199085A successfully refreshed from Google Patents.
Patent US4119895A successfully refreshed from Google Patents.
US4119895A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless d.c. motor with precise speed control
Assignee: Papst Licensing GmbH and Co KG
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Filing: 1977-04-07
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Granted: 1978-10-10
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Expires: 1997-04-07
Abstract
Abstract Speed control for a brushless d.c. motor is made independent of the effects of temperature and aging on the magnetic structure by triggering a rectangular wave pulse generator by voltages produced by the rotation of the motor through a coupling network that makes the trigger time correspond to a certain portion of the rise of voltage so that the influence of the amplitude of the signal on the trigger time will be negligible. The square waves are phase-shifted and integrated to produce a d.c. signal proportional to motor speed on which is superimposed a practically sinusoidal ripple and this signal is fed into a comparator to produce both an error signal from the d.c. component and a commutation control from the a.c. component. The speed is switched between desired precise values by an electronic circuit that controls the duration of the rectangular pulses and makes corresponding adjustments in the integrator and phase shifter.
Inventors
- 👤 Rolf Muller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:23
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06; H02K29/08; A; A01; A01N; A01N43/00; A01N43/72; A01N43/74; A01N43/78; H02P; H02P6/00; H02P6/08
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
149 words
A brushless d.c. motor comprising a permanent magnet rotor; a stator having a winding; means supplied with d.c. current and connected to said stator winding for producing an alternating magnetic field in said stator and having a speed control circuit; means for deriving, from said motor, signals synchronized with the rotation of said rotor; means for generating pulses of a predetermined length; means for triggering the generation of said pulses by said pulse generating means in response to said signals; analog circuit means for phase-shifting and smoothing said pulses for deriving from said pulses a smoothed voltage having a d.c. component and a superimposed a.c. component, and means for feeding said smoothed voltage to said speed control circuit for controlling the speed of said motor by said d.c. component of said voltage while the a.c. component serves to control the armature current and torque cycles as the motor turns.
Claim 2
Dependent Claim
149 words
A brushless d.c. motor comprising a permanent magnet rotor; a stator having a winding; means supplied with d.c. current and connected to said stator winding for producing an alternating magnetic field in said stator and having a speed control circuit; means for deriving, from said motor, signals synchronized with the rotation of said rotor; means for generating pulses of a predetermined length; means for triggering the generation of said pulses by said pulse generating means in response to said signals; analog circuit means for phase-shifting and smoothing said pulses for deriving from said pulses a smoothed voltage having a d.c. component and a superimposed a.c. component, and means for feeding said smoothed voltage to said speed control circuit for controlling the speed of said motor by said d.c. component of said voltage while the a.c. component serves to control the armature current and torque cycles as the motor turns.
Claim 3
Dependent Claim
27 words
A brushless d.c. motor as defined in claim 1, in which said phase-shifting and pulse-smoothing comprise an RC network producing at its output said phase-shifted smoothed voltage.
Claim 4
Dependent Claim
25 words
A brushless d.c. motor as defined in claim 1, in which said signal deriving means are means for deriving said signals from said stator winding.
Claim 5
Dependent Claim
31 words
A brushless d.c. motor as defined in claim 1, in which said signal deriving means comprise an auxiliary motor winding and means for deriving said signals from said auxiliary motor winding.
Claim 6
Dependent Claim
37 words
A brushless d.c. motor as defined in claim 1, in which said motor comprises rotor position sensing means and in which said signal deriving means are means for deriving said signals from said sensing means (FIG. 6).
Claim 7
Dependent Claim
85 words
A brushless d.c. motor as defined in claim 1, in which said pulse generating means comprises a monostable multivibrator circuit (39) and a coupling network (38) connected to the input of said monostable multivibrator circuit for setting the triggering instant (101) of said multivibrator circuit at a predetermined phase angle after the null transition of a signal voltage (47) taken from a winding of said motor in a manner at least approximately independent of the amplitude of the voltage (47) derived from said motor winding.
Claim 8
Dependent Claim
59 words
A brushless d.c. motor as defined in claim 6, in which said coupling network (38) comprises a first coupling member (58) for transmitting the a.c. voltage component of a voltage derived from said motor and a second coupling member (60) for transmitting the d.c. component of the voltage derived from said motor and comprises also a phase shifter (64).
Claim 9
Dependent Claim
51 words
A brushless d.c. motor as defined in claim 1, in which there is provided electronic switching means for switching between predetermined motor speeds, said switching means being contactless means for changing the duration of the output pulses of said pulse generator and for changing the parameters of said phase shifter (40).
Claim 10
Dependent Claim
66 words
A brushless d.c. motor as defined in claim 8, in which said electronic switching means (41) comprises a transistor (89) of which the emitter-collector path is connected in series with a supplementary capacitor (88) of said phase shifter (40) in such a way that when said transistor is in conducting condition, said supplementary capacitor (88) of said phase shifter (40) is operative in said phase shifter.
Claim 11
Dependent Claim
57 words
A brushless d.c. motor as defined in claim 1, in which means are provided for effecting negative feedback (14) dependent upon the amount of current flowing in said motor, said negative feedback means being connected so as to reduce a control voltage applied to said speed control circuit in proportion to the magnitude of said motor current.
Claim 12
Dependent Claim
99 words
A brushless d.c. motor as defined in claim 10, in which said negative feedback means comprises a comparator (42, 86) having an input connected to the output voltage of said phase shifter (40) and another input connected to a tap (43) of a voltage divider (14, 45, 44) supplied with a substantially constant d.c. voltage and having a component resistor (14) thereof connected so that the motor current flows therethrough, said component resistor being so connected in said voltage divider as to provide a negative feedback potential for said motor at said tap (43) when motor current is flowing.
Claim 13
Dependent Claim
42 words
A brushless d.c. motor as defined in claim 1, in which the duration of the respective pulses produced by said pulse generator is approximately 1/2n of the rotation period of the motor, where n is the number of poles of the motor.
Claim 14
Dependent Claim
20 words
A brushless d.c. motor as defined in claim 12, in which the motor has at least three pairs of poles.
References Cited (Backward Citations)
US3999108A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-09 | 1982-04-10 | 1982-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-09 | 1986-04-10 | 1986-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-09 | 1990-04-10 | 1990-10-10 | $7700.00 | Window Closed / Lapsed |