I'm currently working on a design to convert a DC inverter welder to AC, and have just completed the low voltage (25-50V), high current (5-140A) circuitry using EWB5.
It's desirable to also have a built-in high frequency/high voltage (c.10-20KV, negligible current) arc facility across the output cables to make starting the welding arc that much easier, especially when using TIG. However, my output switching stage uses cross-coupled high power MOSFETs which are intolerant of such high voltages. (they *do* have reverse diodes built-in, but it's the forward direction when not conducting I'm concerned about)
Does anyone know of a method of preventing such a high frequency/voltage from finding it's way back down the cable to the MOSFETs ? Maybe it's obvious, but my brain's dried-up. Would a fistful of ferrite rings do it ?
Colin
It's desirable to also have a built-in high frequency/high voltage (c.10-20KV, negligible current) arc facility across the output cables to make starting the welding arc that much easier, especially when using TIG. However, my output switching stage uses cross-coupled high power MOSFETs which are intolerant of such high voltages. (they *do* have reverse diodes built-in, but it's the forward direction when not conducting I'm concerned about)
Does anyone know of a method of preventing such a high frequency/voltage from finding it's way back down the cable to the MOSFETs ? Maybe it's obvious, but my brain's dried-up. Would a fistful of ferrite rings do it ?
Colin