Patent ID: 8581147
Filing Date: 2013-11-12
Classification: B23K,H02M,Y02B,Y02P

Abstract:
1. A three stage power source for an electric arc welding process, said power source comprising an input stage having an AC input and a first fixed DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to said first fixed DC output signal, a network of switches switched at a high frequency with a given duty cycle to convert said input into a first internal AC signal, an isolation transformer with a primary winding driven by said first internal high frequency AC signal and a secondary winding for creating a second internal high frequency AC signal and a rectifier to convert said second internal AC signal into a second fixed DC output signal of said second stage; with a magnitude related to said duty cycle of said switches; and a third stage to convert said second fixed DC output signal to a welding output for welding wherein said input stage has a regulated DC to DC converter including a boost converter having a main inductance, a main rectifier, and a power switch having an active soft switching circuit, said active soft switching circuit of said input stage comprising: an auxiliary switching device and a tank circuit closed by said auxiliary switching device, said tank circuit comprising a resonant inductance coupled in series with said auxiliary switching device, and a resonant capacitance coupled in parallel with said power switch, said resonant capacitance having a first resonant capacitor portion coupled in parallel with said resonant inductance and a second resonant capacitor portion coupled in parallel with said auxiliary switching device.