| 主权项 |
1. A method of providing welding type power, comprising:
pre-regulating an input line voltage to provide a dc bus; and converting the dc bus to a welding type output; wherein the pre-regulating includes SVT and SCT switching a boost convertor, including
maintaining a boost converter switch off, and allowing current to flow through a boost inductor, a snubber inductor, and a first diode, to the dc bus;turning the boost converter switch on and diverting current from the snubber inductor to the switch;reversing the current in the snubber inductor;discharging a second capacitor through a third diode, a first capacitor, and the snubber inductor, thereby transferring energy from the second capacitor to the snubber inductor;diverting current through a fourth diode, the third diode and the first capacitor when the second capacitor is discharged, thereby transferring energy from the snubber inductor to the first capacitor;allowing the voltage on the second capacitor to rise until current begins to flow from the snubber inductor to the first capacitor;diverting current from the second capacitor through a third diode to the second diode;allowing the current flowing from the boost inductor to the snubber inductor to increase until all of the current from the boost inductor flows into the snubber inductor;diverting current from the first capacitor through a fifth diode and the third diode, thereby increasing the voltage on the second capacitor;diverting current from the first capacitor to the first diode; and repeating the SVT and SCT switching of the boost convertor. |
