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EP0147698A2
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Inverter variable dead time for X-Ray generator
Assignee: General Electric Co
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Filing: 1984-12-07
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Granted: —
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Expires: 2004-12-07
Abstract
Abstract In an X-ray generator system having a pulse-width-modulated transistor inverter with associated flywheel diodes, method and apparatus is provided to sense when a diode associated with a non-pulse-width-modulated transistor is conducting and for inhibiting the turning on of that transistor during such period, to thereby avoid the transis- tion from reverse conduction to direct conduction in an uncontrolled manner.
Inventors
- 👤 Carlos Manueco Santurtun
- 👤 Felix Lopez Ceca
- 👤 Jose Ma Quevedo Bengoechea
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 12:54
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/337; H02M3/3376
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
125 words
In an X-ray generator system of the type having an inverter with transistors and associated flywheel diodes arranged in a bridge network to be selectively turned on and off in a predetermined sequence for converting a d.c. source current to an alternating current for application to a high-voltage transformer and, hence, through a rectifier to an X-ray tube which presents a variable load condition to the inverter, a variable dead-time network comprising: (a) inverter driver means for selectively turning the transistors on and off to obtain the d.c. to a.c. conversion function (b) means for sensing when a flywheel diode is conducting and is thereby bypassing its associated transistor; and (c) means for responsively inhibiting said inverter driver means from turning on said associated transistor.
Claim 2
Dependent Claim
125 words
In an X-ray generator system of the type having an inverter with transistors and associated flywheel diodes arranged in a bridge network to be selectively turned on and off in a predetermined sequence for converting a d.c. source current to an alternating current for application to a high-voltage transformer and, hence, through a rectifier to an X-ray tube which presents a variable load condition to the inverter, a variable dead-time network comprising: (a) inverter driver means for selectively turning the transistors on and off to obtain the d.c. to a.c. conversion function (b) means for sensing when a flywheel diode is conducting and is thereby bypassing its associated transistor; and (c) means for responsively inhibiting said inverter driver means from turning on said associated transistor.
Claim 3
Dependent Claim
57 words
A variable dead-time network as set forth in Claim 1 wherein said sensing means includes a comparator having a predetermined reference voltage connected to its negative input terminal and having connected to its positive input terminal a positive d.c. source and the anode of a diode whose cathode is connected to the collector of said non-pulse-width-modulated transistor.
Claim 4
Dependent Claim
43 words
A variable dead-time network as set forth in Claim 2 wherein said inhibiting means includes logic means for receiving the output of said comparator and means to inhibit the turn-on of said transistor when said comparator indicates that said flywheel diode is conducting.
Claim 5
Dependent Claim
105 words
Apparatus for providing a variable dead time in an inverter having a plurality of transistors, with each of said transistors having an associated flywheel diode comprising: (a) means for generating control signals representative of desired voltage output levels; (b) driver means for selectively turning said transistors on and off in response to said control signals; (c) means for sensing when a flywheel diode associated with one of said transistors is conducting to thereby indicate that said one transistor is in a reverse-bias condition; and (d) means for responsively preventing said one transistor from turning on during that period when said associated flywheel diode is conducting.
Claim 6
Dependent Claim
105 words
Apparatus for providing a variable dead time in an inverter having a plurality of transistors, with each of said transistors having an associated flywheel diode comprising: (a) means for generating control signals representative of desired voltage output levels; (b) driver means for selectively turning said transistors on and off in response to said control signals; (c) means for sensing when a flywheel diode associated with one of said transistors is conducting to thereby indicate that said one transistor is in a reverse-bias condition; and (d) means for responsively preventing said one transistor from turning on during that period when said associated flywheel diode is conducting.
Claim 7
Dependent Claim
15 words
An apparatus as set forth in Claim 4 wherein said inverter is a pulse-width-modulated inverter.
Claim 8
Dependent Claim
59 words
An apparatus as set forth in Claim 4 wherein said sensing means comprises a comparator having its negative input terminal connected to a reference voltage and having its positive input terminal connected to both a positive d.c. source and the anode of a diode, with the cathode of said diode being connected to the collector of said one transistor.
Claim 9
Dependent Claim
41 words
An apparatus as set forth in Claim 6 wherein said preventing means comprises a logic circuit for receiving the output of said comparator and for providing representative signals to said driver means to inhibit the turn on of said one transistor.
Claim 10
Independent Claim
75 words
A method for providing a variable dead time in an inverter having a plurality of transistors, with each of said transistors having an associated flywheel diode comprising the steps of: (a) sensing when a flywheel diode associated with one of said transistors is conducting to thereby indicate that said one transistor is in a reverse-bias condition; and (b) responsively inhibiting said one transistor from turning on during that period when said flywheel diode is conducting.
Claim 11
Independent Claim
75 words
A method for providing a variable dead time in an inverter having a plurality of transistors, with each of said transistors having an associated flywheel diode comprising the steps of: (a) sensing when a flywheel diode associated with one of said transistors is conducting to thereby indicate that said one transistor is in a reverse-bias condition; and (b) responsively inhibiting said one transistor from turning on during that period when said flywheel diode is conducting.
References Cited (Backward Citations)
No citation records indexed.
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