US4779183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for selectively controlling an operation mode of a PWM inverter between an asychronous mode and a synchronous mode modulation
Assignee: Hitachi Ltd
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Filing: 1987-07-22
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Granted: 1988-10-18
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Expires: 2007-07-22
Abstract
Abstract A method and apparatus are disclosed for controlling a pulse width modulated (PWM) inverter controlled for ignition by a (PWM) pulse produced with a carrier wave and a modulation wave. The method comprises sampling an amplitude of the modulation wave at a cycle rate related to the frequency of the carrier wave. The modulation wave and the carrier wave are synchronized when the sample modulation wave amplitude has a peak value greater than an amplitude of the carrier wave. The modulation wave and the carrier wave are asynchronized when the sampled modulation wave has a peak value less than the amplitude of the carrier wave.
Inventors
- 👤 Nobuyoshi Mutoh
- 👤 Akiteru Ueda
- 👤 Hideyuki Shimonabe
- 👤 Satoshi Ibori
- 👤 Motonobu Hattori
- 👤 Kenji Nandoh
- 👤 Yuuzi Yamasawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:47
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/539; H02M7/5395; H02M7/505; H02M7/515; H02M7/525; H02M7/527; H02M7/529
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A method for selectively controlling an operation mode of a PWM inverter between an asynchronous and a synchronous modulation mode for outputting a pulse width modulated pulse comprising the following steps: producing a modulation wave and a carrier wave; comparing an amplitude of the modulation wave with an amplitude of the carrier wave to derive an amplitude ratio; producing the pulse width modulated pulse while the modulation wave and the carrier wave are asynchronous when the amplitude ratio is lower than a predetermined value; and producing the pulse width modulated pulse while the modulation wave and the carrier wave are synchronous when the amplitude ratio is larger than the predetermined value.
Claim 2
Independent Claim
111 words
A method for selectively controlling an operation mode of a PWM inverter between an asynchronous and a synchronous modulation mode for outputting a pulse width modulated pulse comprising the following steps: producing a modulation wave and a carrier wave; comparing an amplitude of the modulation wave with an amplitude of the carrier wave to derive an amplitude ratio; producing the pulse width modulated pulse while the modulation wave and the carrier wave are asynchronous when the amplitude ratio is lower than a predetermined value; and producing the pulse width modulated pulse while the modulation wave and the carrier wave are synchronous when the amplitude ratio is larger than the predetermined value.
Claim 3
Dependent Claim
41 words
A method for controlling a PWM inverter according to claim 1 wherein a frequency ratio of the modulation wave and the carrier is constant when the pulse width modulated phase is produced while the modulation wave and the carrier are synchronous.
Claim 4
Dependent Claim
22 words
A method for controlling a PWM inverter according to claim 1 wherein said predetermined value for the amplitude ratio is approximately one.
Claim 5
Independent Claim
102 words
A method for generating a width modulated pulse for an inverter useful in a variable speed drive for an induction motor comprising the steps of: producing a modulation wave signal; producing a carrier wave signal; detecting a ratio of an amplitude of the modulation wave relative to the carrier wave; comparing the ratio with a predetermined value; synchronizing the modulation wave signal and the carrier wave signal when the ratio bears a first predetermined relationship to the predetermined value; and, asynchronizing the carrier wave signal and the modulation wave signal when the ratio bears a second predetermined relationship to the predetermined value.
Claim 6
Independent Claim
102 words
A method for generating a width modulated pulse for an inverter useful in a variable speed drive for an induction motor comprising the steps of: producing a modulation wave signal; producing a carrier wave signal; detecting a ratio of an amplitude of the modulation wave relative to the carrier wave; comparing the ratio with a predetermined value; synchronizing the modulation wave signal and the carrier wave signal when the ratio bears a first predetermined relationship to the predetermined value; and, asynchronizing the carrier wave signal and the modulation wave signal when the ratio bears a second predetermined relationship to the predetermined value.
Claim 7
Dependent Claim
105 words
A control method for a PWM inverter which is controlled for ignition by a pulse width modulated pulse produced with a carrier wave having a first frequency and an amplitude and a modulation wave having a second frequency and amplitude comprising: sampling the amplitude of the modulation wave and the carrier wave; synchronizing the modulation wave and the carrier wave when the sampled modulation wave amplitude has a peak value greater than the amplitude of the carrier wave; and, asynchronizing the modulation wave and the carrier wave when the sampled modulation wave amplitude has a peak value less than the amplitude of the carrier wave.
Claim 8
Dependent Claim
105 words
A control method for a PWM inverter which is controlled for ignition by a pulse width modulated pulse produced with a carrier wave having a first frequency and an amplitude and a modulation wave having a second frequency and amplitude comprising: sampling the amplitude of the modulation wave and the carrier wave; synchronizing the modulation wave and the carrier wave when the sampled modulation wave amplitude has a peak value greater than the amplitude of the carrier wave; and, asynchronizing the modulation wave and the carrier wave when the sampled modulation wave amplitude has a peak value less than the amplitude of the carrier wave.
Claim 9
Dependent Claim
166 words
A control apparatus for a PWM inverter comprising: a PWM inverter; means for receiving an output frequency command for said PWM inverter and producing a modulation period signal in accordance with a pulse width modulation period; voltage command means for issuing a voltage command for said inverter; modulation wave generation means for generating a sine wave modulation wave having an amplitude proportional to said voltage command, at a frequency determined by the inverter frequency command; carrier generation means for generating a ramp wave carrier at a frequency determined by a carrier frequency command; mode command means for comparing the voltage command with a reference to command synchronous or asynchronous mode; phase matching means for matching phases of the modulation period signal and the carrier; selection means for selecting said phase matching means by a mode command of said mode command means; and pulse generation means for comparing the modulation wave with the carrier to generate a pulse width modulated pulse for application to said PWM inverter.
Claim 10
Dependent Claim
166 words
A control apparatus for a PWM inverter comprising: a PWM inverter; means for receiving an output frequency command for said PWM inverter and producing a modulation period signal in accordance with a pulse width modulation period; voltage command means for issuing a voltage command for said inverter; modulation wave generation means for generating a sine wave modulation wave having an amplitude proportional to said voltage command, at a frequency determined by the inverter frequency command; carrier generation means for generating a ramp wave carrier at a frequency determined by a carrier frequency command; mode command means for comparing the voltage command with a reference to command synchronous or asynchronous mode; phase matching means for matching phases of the modulation period signal and the carrier; selection means for selecting said phase matching means by a mode command of said mode command means; and pulse generation means for comparing the modulation wave with the carrier to generate a pulse width modulated pulse for application to said PWM inverter.
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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) | 1991-10-18 | 1992-04-18 | 1992-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-18 | 2000-04-18 | 2000-10-18 | $7700.00 | Window Closed / Lapsed |