I have often seen copper foil used in high power transformers for the primary and secondary windings, especially at higher frequencies where the AC effects and losses are dominant. In general, how plausible is the use of such copper foils in higher voltage designs such as a fly-back step-up transformer? The transformer will operate at least 500kHz, with a 250VDC input and 4 x 750VDC output windings that are connected in series and to voltage doublers.
Is there an argument that could be made that the foil is suitable for the primary but not the secondary, or could these foils be used for both, or none at all? Why? I am unsure on how the capacitance of the transformer is effected by such winding geometries -- still searching for some more data on this. I was thinking of using foil on the primary where the higher current is and I cannot source Litz wire, and then using standard low gauge wire that is triple insulated on the secondaries since it is low current to achieve the isolation between the primary and secondary windings. Teledyne for example has 13kV triple insulated wire but this is also proving difficult to source in lower quantities for a prototype.
Is there an argument that could be made that the foil is suitable for the primary but not the secondary, or could these foils be used for both, or none at all? Why? I am unsure on how the capacitance of the transformer is effected by such winding geometries -- still searching for some more data on this. I was thinking of using foil on the primary where the higher current is and I cannot source Litz wire, and then using standard low gauge wire that is triple insulated on the secondaries since it is low current to achieve the isolation between the primary and secondary windings. Teledyne for example has 13kV triple insulated wire but this is also proving difficult to source in lower quantities for a prototype.