Method for contactlessly striking an arc and welding current source for carrying out a striking process

• Main Authors: PRINZ ANDREAS, MUSIL FRANZ PETER
• Format: Patent
• Language: Chinese; English
• Published: 26.06.2020
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; CLADDING OR PLATING BY SOLDERING OR WELDING; CONTROL OR REGULATION THEREOF; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRICITY; GENERATION; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

The invention relates to a method for contactlessly striking an arc (L) between an electrode (3) and a workpiece (4), which is to be welded, for carrying out a welding process, wherein a welding current (I) and a welding voltage (U) are provided at an output (2) of a welding current source (1), wherein the welding current source (1) contains a resonance converter (5) for generating a periodicallychanging, preferably substantially sawtooth-like, no-load welding voltage (ULL) with voltage maxima (ULL,max) which recur periodically at a repetition frequency (fW), and also a welding current source(1) for carrying out the striking process. In order to achieve reliable contactless striking of the arc (L) without complicated circuitry, the resonance converter (5) is formed by a series-parallel resonance converter, and temporally synchronous high-frequency pulses (UI,HF) are superimposed on the no-load welding voltage (ULL) in the region of at least some periodically recurring voltage maximum(ULL,max) of the no-load w