Optimized transformer for arc striking applications

An in-line arc striking power converter used in electric welding applications needs to be galvanically isolated with a high-frequency power transformer. A feature of the particular circuit application is that the magnetising inductance of the isolation transformer is used in a resonant circuit to generate 2 kV at 500 kHz. Two loading conditions exist for the transformer, namely a large voltage at the secondary during open circuit prior to arc striking and a secondary current typically larger than 100 A during welding itself. Possible transformer configurations are investigated which include an air core and a number of ferrite cored transformers. Analysis and experimental results of the transformers are presented and an optimum configuration is identified