US5444592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Portable power unit
Assignee: Honda Motor Co Ltd
•
Filing: 1994-09-15
•
Granted: 1995-08-22
•
Expires: 2014-09-15
Abstract
Abstract A portable power unit has a protective circuit for cutting off an output current from the power unit when the power unit is in an overload state. An amount of the output current is detected. An output voltage from the power unit is reduced when the amount of the output current detected reaches a first threshold value, thereby preventing the protective circuit from undesirably operating for one power unit when it is connected for another for parallel operation. When the amount of the output current decreases to a second threshold value which is smaller than the first threshold value, with the power unit being in a state in which the output voltage is reduced, the voltage-reducing operation is canceled.
Inventors
- 👤 Motohiro Shimizu
- 👤 Masashi Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:03
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/06; H02H7/062
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
321 words
A portable power unit having an alternating current generator having a primary output winding, a rectifier circuit for rectifying an alternating current generated by said primary output winding into a direct current, a smoothing circuit for smoothing said direct current from said rectifier circuit to produce a smoothed direct current, an invertor circuit responsive to a driving signal, for effecting switching control of said smoothed direct current, electric current-detecting means for detecting an amount of an output current from said invertor circuit, and a protective circuit, said protective circuit comprising: means for cutting off said output current when said amount of said output current detected by said electric current-detecting means increases to a current value which can be assumed when said power unit is in an overload state; voltage-reducing means for progressively reducing an output voltage from said power unit as time elapses, within a predetermined voltage range, when said amount of said output current detected by said electric current-detecting means increases to a first threshold value which is smaller than said current value which can be assumed when said power unit is in said overload state; and canceling means for canceling a voltage reduction operation of said voltage-reducing means, when said amount of said output current decreases to a second threshold value which is smaller than said first threshold value, while said power unit is in a state in which said output voltage is reduced to a lower limit value of said predetermined voltage range by said voltage-reducing means; said protective circuit cutting off said output current by stopping said switching operation of said invertor circuit when said amount of said output current increases to said current value which can be assumed when said power unit is in said overload state, while said power unit is in said state in which said output voltage is reduced to said lower limit value of said predetermined voltage range by said voltage-reducing means.
Claim 2
Dependent Claim
321 words
A portable power unit having an alternating current generator having a primary output winding, a rectifier circuit for rectifying an alternating current generated by said primary output winding into a direct current, a smoothing circuit for smoothing said direct current from said rectifier circuit to produce a smoothed direct current, an invertor circuit responsive to a driving signal, for effecting switching control of said smoothed direct current, electric current-detecting means for detecting an amount of an output current from said invertor circuit, and a protective circuit, said protective circuit comprising: means for cutting off said output current when said amount of said output current detected by said electric current-detecting means increases to a current value which can be assumed when said power unit is in an overload state; voltage-reducing means for progressively reducing an output voltage from said power unit as time elapses, within a predetermined voltage range, when said amount of said output current detected by said electric current-detecting means increases to a first threshold value which is smaller than said current value which can be assumed when said power unit is in said overload state; and canceling means for canceling a voltage reduction operation of said voltage-reducing means, when said amount of said output current decreases to a second threshold value which is smaller than said first threshold value, while said power unit is in a state in which said output voltage is reduced to a lower limit value of said predetermined voltage range by said voltage-reducing means; said protective circuit cutting off said output current by stopping said switching operation of said invertor circuit when said amount of said output current increases to said current value which can be assumed when said power unit is in said overload state, while said power unit is in said state in which said output voltage is reduced to said lower limit value of said predetermined voltage range by said voltage-reducing means.
Claim 3
Dependent Claim
152 words
A portable power unit according to claim 1, including: output voltage phase-detecting means for detecting a phase of voltage of said alternating current output having said predetermined frequency and for generating a signal indicative of the detected phase of voltage of said alternating current output; output current phase-detecting means for detecting a phase of current of said alternating current output having said predetermined frequency and for generating a signal indicative of the detected phase of current of said alternating current output; phase difference-detecting means for detecting a phase difference between the detected phase of voltage and the detected phase of current and for generating a signal indicative of the detected phase difference; and feedback means for controlling said driving signal supplied to said invertor circuit in a feedback manner based on said signal indicative of the detected phase difference outputted from said phase difference-detecting means, such that the phase difference is reduced.
Claim 4
Dependent Claim
42 words
A portable power unit according to claim 2, wherein said protective circuit includes means for cutting off said output current when said output current has continued to be equal to or larger than said first threshold value over a predetermined time period.
Claim 5
Dependent Claim
42 words
A portable power unit according to claim 1, wherein said protective circuit includes means for cutting off said output current when said output current has continued to be equal to or larger than said first threshold value over a predetermined time period.
Claim 6
Dependent Claim
53 words
A portable power unit according to claim 1, wherein: said portable power unit has an output voltage vs. output current characteristic such that as the output current increases, the output voltage decreases; and said portable power unit is operable in single operation or in parallel operation with at least one additional power unit.
Claim 7
Dependent Claim
89 words
A portable power unit according to claim 5, wherein: said portable power unit operates in parallel with at least one additional power unit; and said first and second threshold values are set to values dependent upon said output voltage vs. output current characteristic of said portable power unit and a variation between said output voltage vs. output current characteristic of said portable power unit and an output voltage vs. output current characteristic of said at least one additional power unit with which said portable power unit operates in parallel.
Claim 8
Dependent Claim
25 words
A portable power unit according to claim 1, wherein said output current is held substantially constant while said voltage-reducing means is reducing said output voltage.
Claim 9
Dependent Claim
89 words
A portable power unit according to claim 7, wherein: said portable power unit operates in parallel with at least one additional power unit; and said first and second threshold values are set to values dependent upon said output voltage vs. output current characteristic of said portable power unit and a variation between said output voltage vs. output current characteristic of said portable power unit and an output voltage vs. output current characteristic of said at least one additional power unit with which said portable power unit operates in parallel.
References Cited (Backward Citations)
US4013925A
Cited
JPS5620782A
Cited
US4629966A
Cited
JPS62145440A
Cited
US4751629A
Cited
US5077485A
Cited
US5258700A
Cited
US5282124A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-08-21 | 1999-02-20 | 1999-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-21 | 2003-02-20 | 2003-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-21 | 2007-02-20 | 2007-08-22 | $7700.00 | Window Closed / Lapsed |