US3604995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Generator for producing a width-modulated square voltage
Assignee: Danfoss AS
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Filing: 1968-08-27
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Granted: 1971-09-14
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Expires: 1988-08-27
Abstract
Abstract Apparatus producing a width modulated square wave for use in a motor control circuit controlling the speed of an alternatingcurrent motor. A low frequency three-phase generator with stationary components develops three wave outputs integrated and summed with a high frequency wave signal, in a summation circuit, produced by a frequency generator. The sign of the outputs of the summation circuit is ascertained by zero level detectors and employed for controlling the motor speed. A direct-current control voltage is applied to the apparatus to control the amplitude of the high and low frequency waves.
Inventors
- 👤 Arne Jensen
- 👤 Tom Kastrup Petersen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:38
CPC Classifications
H; H02; H02P; H02P27/00; H02P27/04; H02P27/06; H02P27/08; H03; H03K; H03K7/00; H03K7/08; H02P27/047
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
103 words
Apparatus for producing a width-modulated square wave for controlling the speed of alternating-current motors comprising, first generator means for generating a low frequency first signal defining an alternating-current wave having trapezoidal shape in which each half cycle is divided into three equal time regions, said low-frequency signal having a constant amplitude and a variable frequency second generator means generating a higher frequency second signal having a constant repetition frequency and varying amplitude, and defining an alternating current wave in which each half cycle defines a triangle; and means to receive the first and second signal and develop therefrom a widthmodulated square wave voltage.
Claim 2
Dependent Claim
103 words
Apparatus for producing a width-modulated square wave for controlling the speed of alternating-current motors comprising, first generator means for generating a low frequency first signal defining an alternating-current wave having trapezoidal shape in which each half cycle is divided into three equal time regions, said low-frequency signal having a constant amplitude and a variable frequency second generator means generating a higher frequency second signal having a constant repetition frequency and varying amplitude, and defining an alternating current wave in which each half cycle defines a triangle; and means to receive the first and second signal and develop therefrom a widthmodulated square wave voltage.
Claim 3
Dependent Claim
140 words
The invention as set forth in claim 1, in which said first generator means for generating a low-frequency signal comprises a three-phase generator including three identical units coupled together in a cascade arrangement, and each having an output conductor each said unit comprising zero-level detector means having an output conductor and having an input conductor coupled to the output conductor of the just preceding unit in said cascade arrangement, limiter means having a first input conductor coupled to the output conductor of its corresponding zero-detector means, said limiter means having a signal output conductor and a second input conductor for connection to a control signal for varying the signal output amplitude therefrom, and integrating circuit means for integrating the output of said limiter means to generate said wave defining a trapezoid at said integrating circuit means of each said unit.
Claim 4
Dependent Claim
94 words
The invention as set forth in claim 1, in which said second generator means for generating a higher frequency comprises an oscillator having a output terminal, a flip-flop connected to said output terminal of said oscillator and having two output terminals producing signals out of phase with each other, two parallel limiters connected respectiveLy to said two output terminals, each said limiter having an output conductor, an integrating circuit means connected to said two limiter output conductors for summing and integrating the limiter outputs and developing therefrom triangular waves corresponding to said second signal.
Claim 5
Dependent Claim
40 words
The invention as set forth in claim 3, in which said integrating circuit means comprises means including an amplifier for superimposing on peaks of said second signal trianglar waves a steep-edged signal of shorter duration than each triangular half cycle.
Claim 6
Dependent Claim
59 words
Apparatus according to claim 1, including means to apply a direct current voltage of plus and minus polarity to said first and said second generator means for varying the frequency of the low-frequency signal proportionately to the value of said direct-current signal and varying the amplitude of the higher-frequency signal inversely proportional to the value of said direct-current signal.
Claim 7
Dependent Claim
39 words
Apparatus according to claim 1, including means to apply a direct-current voltage of plus and minus polarity to said first generator means to vary the frequency of the low frequency signal proportionately to the value of said direct-current signal.
Claim 8
Dependent Claim
104 words
Apparatus according to claim including 1, in which said second means comprises a square wave generator and an integrator connected in series combination with said square wave generator, said series combination being connected in parallel with said first generator means, and said integrator having an output conductor, and in which said first generator means comprises a three-phase generator for generating three-phase outputs, a summation network having said three phase outputs connected thereto, means applying the output conductor of the integrator to each phase output received in said summation network, and a zero-level detector for each phase connected respectively in series with said summation networks.
Claim 9
Dependent Claim
101 words
Apparatus according to claim 1, in which said first generator means comprises a three-phase generator having three output conductors, and in which said second generator means comprises a square wave generator and an integration circuit connected in series combination, said combination being connected in parallel with said three-phase generator, and a summation network connected to said three-phase generator for adding the output of said integrator to each output conductor of the three-phase generator, and means to apply a direct-current control signal of plus and minus polarity to said three-phase generator for controlling the amplitude of the outputs of the three-phase generator.
Claim 10
Dependent Claim
44 words
Apparatus according to claim 8, comprising a slope detector having said integrator output conductor connected thereto for developing a direct-current control signal, to said first generator means to vary the frequency of the low frequency signal proportionately to the value of said direct-current signal.
Claim 11
Dependent Claim
37 words
Apparatus according to claim 9, including a control circuit connected between said integrator and said square wave generator in series therewith said control circuit having means for receiving a control signal corresponding to said direct-current control signal.
References Cited (Backward Citations)
US3402353A
Cited
US3440566A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-13 | 1975-03-15 | 1975-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-13 | 1979-03-15 | 1979-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-13 | 1983-03-15 | 1983-09-14 | $7700.00 | Window Closed / Lapsed |