Power convertor with low loss switching
First Claim
1. A welding power supply comprising:
- an input rectifier configured to receive an input line voltage and provide a rectified voltage on an output;
a pre-regulator connected to receive as an input the output of the rectifier and provide a dc bus as an output; and
a convertor, connected to receive the output of the pre-regulator and provide a welding output;
wherein the pre-regulator is an SVT and a SCT switched convertor.
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Accused Products
Abstract
A welding power supply includes an input rectifier that receives sinusoidal or alternating line voltage and provides a rectified voltage. A pre-regulator provides a dc bus and a convertor, such as a boost convertor, provides a welding output. The pre-regulator is an SVT (slow voltage transition) and an SCT (slow current transition) switched convertor. It may include a snubber circuit having a diode that is SVT switched. Also, the boost convertor may be SVT and SCT switched. The pre-regulator preferably includes a power factor correction circuit. The power source includes, in one embodiment, an inverter having a snubber circuit having a first switch in anti-parallel with a first diode, and a second switch in anti-parallel with a second diode. The first switch and first diode are connected in series with the second switch and the second diode, and the first and second switches are connected in opposing directions, to form a switched snubber.
31 Citations
22 Claims
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1. A welding power supply comprising:
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an input rectifier configured to receive an input line voltage and provide a rectified voltage on an output;
a pre-regulator connected to receive as an input the output of the rectifier and provide a dc bus as an output; and
a convertor, connected to receive the output of the pre-regulator and provide a welding output;
wherein the pre-regulator is an SVT and a SCT switched convertor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of providing welding power, comprising the steps of:
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rectifying an input line voltage;
pre-regulating the input line voltage to provide a dc bus; and
converting the dc bus to a welding output;
wherein the step of pre-regulating includes SVT and SCT switching a boost convertor. - View Dependent Claims (8, 9, 10)
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11. A welding power supply comprising:
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an input rectifier means for receiving an input line voltage and providing a rectified voltage;
a pre-regulator means for receiving the rectified voltage and providing a dc bus, wherein the pre-regulator means is connected to the rectifier means; and
a convertor means for receiving the output of the pre-regulator means and provide a welding output, wherein the converter means is connected to the pre-regulator means;
wherein the pre-regulator means includes SVT and SCT switching means. - View Dependent Claims (12, 13, 16, 17, 20, 21, 22)
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14. A welding power supply comprising:
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an input rectifier configured to receive an input line voltage and provide a rectified voltage on an output;
a pre-regulator connected to receive as an input the output of the rectifier and provide a dc bus as an output; and
an invertor, connected to receive the output of the pre-regulator and provide a welding output;
wherein the inverter includes a snubber circuit having a first switch in anti-parallel with a first diode, and a second switch in anti-parallel with a second diode, and wherein the combination of the first switch and first diode are connected in series with the combination of the second switch and the second diode, and wherein the first and second switches are connected in opposing directions.
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15. A welding power supply comprising:
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a first current path through a transformer in a first direction, the first current path including at least a first switch with an anti-parallel first diode;
a second current path through the transformer in a second direction, the second current path including at least a second switch with an anti-parallel second diode;
a snubber, including a current path having a third switch with an anti-parallel third diode, a fourth switch with an anti-parallel fourth diode, wherein the third switch and anti-parallel diode are in series with, and oppositely directed from, the fourth switch and anti-parallel diode, and at least one is snubber capacitor.
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18. The power supply of 15 wherein the at least one snubber capacitor is in series with the third and fourth switches and anti-parallel diodes.
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19. A method of providing welding power comprising the steps of:
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turning on a first power switch and a first snubber switch, and allowing current to flow through the first power switch, a first dc bus, a first power capacitor, and in a first direction through a transformer;
turning the first power switch off and allowing current to flow through the first snubber switch, a second snubber diode, a snubber capacitor, and through the transformer in the first direction, while the first power switch is turning off, to provide a slow voltage transition off;
allowing current to flow through a second anti-parallel power diode, a second DC bus, a second power capacitor, and through the transformer in the first direction, while the first power switch is continuing to turn off, to continue providing a slow voltage transition off;
turning off the first snubber switch;
turning on a second power switch and a second snubber switch after the first power switch is off, and allowing current to flow through the second power switch, the transformer in a second direction, the second power capacitor, and the second bus;
turning the second power switch off and allowing current to flow through the second snubber switch, a first snubber diode, the transformer in the second direction, and a snubber capacitor, while the second power switch is turning off, to provide a slow voltage transition off;
allowing current to flow through a first power diode, the transformer in the second direction, and the first power capacitor, while the second power switch is turning off, to provide a slow voltage transition off;
turning off the second snubber switch;
and repeating these steps.
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Specification