US6496397B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inverter device
Assignee: Hitachi Ltd
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Filing: 2001-04-06
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Granted: 2002-12-17
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Expires: 2021-04-06
Abstract
Abstract An inverter device has a three-phase inverter for converting DC electric power into AC power for supplement to an AC electric motor and a control device operatively associated therewith, and the control device includes a phase current detection section for outputting a phase current waveform based on a DC input current and an operational processor section for performing operational processing for control of said inverter device based on the phase current waveform. Thereby, the inverter device can be constructed to be very compact.
Inventors
- 👤 Keijiro Sakai
- 👤 Toshiaki Okuyama
- 👤 Kinya Nakatsu
- 👤 Seiji Ishida
- 👤 Hiroshi Fujii
- 👤 Junji Kato
- 👤 Masahiro Hiraga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:34
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; H02M7/53875; H02P; H02P27/00; H02P27/04; H02P27/06; H02P27/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
179 words
An inverter device comprising a three-phase inverter for converting DC electric power into AC power for supplement to an AC electric motor and a control device operatively associated therewith, wherein said control device comprises a first sample-hold circuit for sample-holding a DC input current of the inverter in a gate state for causing a positive side arm switching element or negative side arm switching element of the three-phase inverter to turn on within a time period corresponding to a single phase thereof while letting it turn off within periods corresponding to the remaining two phases, and a second sample-hold circuit for sample-holding a DC input current of the inverter in a gate state which causes it to turn on within periods corresponding to two phases while turning it off within a period corresponding to the remaining one phase, and also comprises means for varying an output frequency or output voltage of the inverter in accordance with output values of said first and second sample-hold circuits, the output values varying with a 120-degree phase period of inverter output voltage phases.
Claim 2
Dependent Claim
179 words
An inverter device comprising a three-phase inverter for converting DC electric power into AC power for supplement to an AC electric motor and a control device operatively associated therewith, wherein said control device comprises a first sample-hold circuit for sample-holding a DC input current of the inverter in a gate state for causing a positive side arm switching element or negative side arm switching element of the three-phase inverter to turn on within a time period corresponding to a single phase thereof while letting it turn off within periods corresponding to the remaining two phases, and a second sample-hold circuit for sample-holding a DC input current of the inverter in a gate state which causes it to turn on within periods corresponding to two phases while turning it off within a period corresponding to the remaining one phase, and also comprises means for varying an output frequency or output voltage of the inverter in accordance with output values of said first and second sample-hold circuits, the output values varying with a 120-degree phase period of inverter output voltage phases.
Claim 3
Dependent Claim
38 words
An inverter device as defined in claim 1 wherein said control device further comprises means for reducing the output frequency of the inverter when the sample-hold circuit output value goes beyond a preset level as established in advance.
Claim 4
Dependent Claim
74 words
An inverter device as defined in claim 1 wherein said control device further comprises means for calculating a torque current or an excitation current of the AC electric motor on the basis of a reference phase with an inverter frequency command integrated and said sample-hold circuit output value, and means for varying the output frequency or output voltage of the inverter in accordance with a calculated value of said torque current or excitation current.
Claim 5
Dependent Claim
50 words
An inverter device as defined in claim 1 wherein said control device further comprises means for varying the output frequency or output voltage of the inverter in accordance with said sample-hold circuit output values near a maximal value and a minimal value of each phase AC voltage of the inverter.
Claim 6
Dependent Claim
36 words
An inverter device of claim 1 wherein said control device further comprises means for varying the output frequency or output voltage of the inverter in accordance with an average change of the sample-hold circuit output value.
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) | 2005-12-16 | 2006-06-17 | 2006-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-12-16 | 2010-06-17 | 2010-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-12-16 | 2014-06-17 | 2014-12-17 | $7700.00 | Window Closed / Lapsed |