Patent US4259581A successfully refreshed from Google Patents.
US4259581A
Expired / Lapsed
US
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High-power diagnostical X-ray equipment with thyristor converter
Assignee: Medicor Muvek
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Filing: 1979-04-04
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Granted: 1981-03-31
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Expires: 1999-04-04
Abstract
Abstract An inverter for diagnostic X-ray equipment, comprising a thyristor bridge with an input diagonal connected in series with two commutating inductances across a DC power supply, is provided with a start-stop circuit which includes an ancillary thyristor connected in series with a diode and a current-limiting impedance across one of the bridge arms. On start-up, the ancillary thyristor is triggered simultaneously with the diagonally opposite bridge thyristor in order to connect the current-limiting impedance in series with the AC output diagonal of the bridge during the first half-period; for a quick cutoff, the ancillary thyristor and the associated bridge thyristor are turned on together whereby two previously charged quenching capacitors, one of them included in the start-stop circuit, are discharged through the commutating inductance in series with the associated bridge arm to terminate conduction in another bridge arm fed through the same commutating inductance. A protective unit connected across the input diagonal of the bridge includes a further capacitor, charged from an auxiliary voltage source, which reverse-biases the bridge thyristors by way of another thyristor fired upon detection of a short circuit or overload.
Inventors
- 👤 Peter Csontos
- 👤 Laszlo Henter
- 👤 Laszlo Kalman
- 👤 Tibor Kondor
- 👤 Istvan Wein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:47
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/10; H05G1/20; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/505; H02M7/515; H02M7/5152; H05G1/22; H02M1/00; H02M1/0083; H02M1/0085
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
166 words
A circuit arrangement for the controlled energization of diagnostic X-ray equipment with alternating current, comprising: a supply of direct current provided with a pair of output terminals; an inverter including a bridge with four switching thyristors in respective arms thereof defining a DC input diagonal and an AC output diagonal; inductance means connected in series with said input diagonal across said terminals; a set of four commutating capacitors inserted between said terminals and opposite ends of said output diagonal; an ancillary thyristor connected in series with a current-limiting impedance across one of said switching thyristors; and control means for alternately firing diagonally opposite pairs of said switching thyristors to the exclusion of said ancillary thyristor in respective halves of a succession of operating periods following a first half-period in which said ancillary thyristor is fired to the exclusion of said one of said switching thyristors but concurrently with the diagonally opposite switching thyristor whereby said current-limiting impedance is effectively connected in series with said output diagonal.
Claim 2
Dependent Claim
166 words
A circuit arrangement for the controlled energization of diagnostic X-ray equipment with alternating current, comprising: a supply of direct current provided with a pair of output terminals; an inverter including a bridge with four switching thyristors in respective arms thereof defining a DC input diagonal and an AC output diagonal; inductance means connected in series with said input diagonal across said terminals; a set of four commutating capacitors inserted between said terminals and opposite ends of said output diagonal; an ancillary thyristor connected in series with a current-limiting impedance across one of said switching thyristors; and control means for alternately firing diagonally opposite pairs of said switching thyristors to the exclusion of said ancillary thyristor in respective halves of a succession of operating periods following a first half-period in which said ancillary thyristor is fired to the exclusion of said one of said switching thyristors but concurrently with the diagonally opposite switching thyristor whereby said current-limiting impedance is effectively connected in series with said output diagonal.
Claim 3
Dependent Claim
110 words
A circuit arrangement as defined in claim 1, further comprising a quenching capacitor connected across a series combination of said ancillary thyristor and a commutating inductance forming part of said inductance means, said control means being responsive to a stop command for firing said one of said switching thyristors concurrently with said ancillary thyristor at the end of a final half-period in which another switching thyristor in series with said commutating inductance is conductive and in which said quenching capacitor is charged via said current-limiting impedance, thereby discharging said quenching capacitor together with one of said commutating capacitors through said commutating inductance and terminating conduction of said other switching thyristor.
Claim 4
Dependent Claim
35 words
A circuit arrangement as defined in claim 2, further comprising a diode inserted in the discharge path of said quenching capacitor in series with said current-limiting impedance and in aiding relationship with said ancillary thyristor.
Claim 5
Dependent Claim
65 words
A circuit arrangement as defined in claim 1, 2 or 3, further comprising a reverse-biasing capacitor, an auxiliary power source connected across said reverse-biasing capacitor for charging same, and electronic switch means operable by said control means upon detection of an overload for connecting said reverse-biasing capacitor across said input diagonal in bucking relationship with said supply to cut off conduction of said switching thyristors.
Claim 6
Dependent Claim
39 words
A circuit arrangement as defined in claim 4 wherein a protective diode is connected in parallel with said reverse-biasing capacitor, further comprising an R/C network and a quenching inductance in series with said protective diode and said reverse-biasing capacitor.
Claim 7
Dependent Claim
121 words
A circuit arrangement as defined in claim 1, 2 or 3 wherein said supply includes a bridge circuit with a plurality of rectifying thyristors and as many rectifying diodes having junctions connected to respective phase leads of a polyphase network, a storage capacitor connected across said bridge circuit, a mode-selector switch inserted between said storage capacitor and said rectifying diodes, and a further diode connecting said storage capacitor independently of said mode-selector switch to a neutral point of said polyphase network, said rectifying thyristors having gates connected to said control means for staggered energization to charge said storage capacitor via said rectifying diodes in a conducting state of said mode-selector switch and via said further diode in a nonconducting state thereof.
Claim 8
Dependent Claim
24 words
A circuit arrangement as defined in claim 6, further comprising a charging inductance connected in series with a flywheel diode across said storage capacitor.
References Cited (Backward Citations)
US3294299A
Cited
US3428809A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-30 | 1984-09-29 | 1985-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-30 | 1988-09-29 | 1989-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-30 | 1992-09-29 | 1993-03-31 | $7700.00 | Window Closed / Lapsed |