Field enhancement optimization of an air-cored spiral strip pulse transformer

The structure of a compact air-cored high-voltage spiral strip pulse transformer is relatively simple, but considerable attention is needed to prevent breakdown between transformer windings. Since thickness of the winding conductors in the spiral strip type is in the order of submillimeter, field enhancement at the edges of the winding conductor is very high. It is, therefore, important to find proper winding parameters to reduce the field enhancement and, thus, to make the system compact. An insulator structure, which has multilayered dielectric materials with different dielectric constants, has been considered and numerically simulated. The field enhancement factor has been defined and obtained as a function of the conductor edge shape, dielectric constants of the insulation layer, and the thickness of multilayered dielectric material. Optimum design parameters are obtained to reduce the field enhancement at the edge of the windings.