Loss Computation Method for Litz Cables With Emphasis on Bundle-Level Skin Effect

An efficient method is proposed for the numerical simulation of the bundle-level skin effect and its consequences arising in certain types of litz wires. The method is based on a probabilistic approach. The theory presented allows characterization of the repartition of currents between bundles and predicts some unexpected unique features. The method is tested on a coil unit that is used for inductive wireless power transfer. Simulations are verified by experimental data.