An AC Resistance Optimization Method Applicable for Inductor and Transformer Windings with Full Layers and Partial Layers

This paper proposes an ac resistance optimization method applicable for both inductor and transformer windings with full layers and partial layers. The proposed method treats the number of layers of the windings as a design variable instead of as a predefined parameter, compared to existing methods. The window height and width of magnetic cores and the insulation requirements are introduced as boundary conditions in the optimization process. The optimization can be realized simply by mathematical design map analyses instead of iteration programs. Moreover, a corresponding closed form expression of ac resistance of windings with partial layers is proposed. The developed analytical equation is verified by both Finite Element Method (FEM) simulations and experimental results from two transformer prototypes. A case study of a transformer design with partial layer windings for a LCC resonant circuit is presented with experimental verifications to demonstrate the optimization method.