Patent ID: 6504132
Filing Date: 2003-01-07
Classification: B23K

Abstract:
An electric arc welder with a variable AC voltage input of up to 600 VAC and a rectifier to provide a DC link, a driven high frequency boost stage with first and second leads connected to said DC link, said boost stage comprising an inductor, a first series output branch with a first primary winding connected to said first lead and a first capacitor connected to said second lead, a second series output branch with a second primary winding connected to said second lead and a second capacitor connected to said first lead and a high frequency operated switch between said leads and having an opened condition charging said capacitors by current through said primary windings in a first direction and discharging said inductor and a closed condition charging said inductor through said primary windings by current in a second direction and discharging said inductor to charge said capacitors, said switch operated by a power factor control circuit at a frequency greater than about 18 kHz, said boost stage having an AC output stage comprising the secondary winding network of a transformer powered by current flow in said first and second primary windings, a rectifier for converting said AC output to a first DC voltage and an output converter for converting said first DC voltage to a second DC voltage connected across the arc of a welding station and having a controlled weld current or voltage.