Overview of helical foil winding design for planar magnetic components

This paper further elaborates on the topic of conductor optimization for planar helical foil windings. Part 1 of this work briefly covers the classical design methods and new schemes suggested for ac-inductors supported by two case studies. Optimisation of the windings used in filter inductors, carrying both ac- and dc-currents simultaneously, are handled in Part 2 of the publication. Winding shaping techniques, formerly used for cylindrical conductor windings, are adapted for helical foil windings placed in gapped cores. The concept of varying conductor thickness is further used here to achieve substantial reduction in overall losses with the further advantage of drastically reducing the time needed for obtaining the optimal winding shape. The calorimetric methods used to verify results experimentally are also included in this part.