Litz Wire Pulsed Power Air Core Coupled Inductor

A methodology for designing high-current air core pulsed power coupled inductors is presented with emphasis on simplicity. Standard inductor design is based on derated current densities and magnetic flux densities to make the most efficient utilization of materials, but the presented pulsed power inductors have low duty cycle and are designed based on impedance and physical size. The frequency content of applied pulses manifests as strong eddy currents that cause high ac resistance. The use of litz wire is justified for extremely low-resistance inductors and, in our case, resulted in a design that is smaller, lighter, and less costly than when using conventional conductors. Wheeler's formula is used to estimate the optimal geometry, and finite-element analysis is used to verify and finalize the design. Several 2.2-μH inductors were successfully designed and built to within 10% tolerance.