Litz Wire and Uninsulated Twisted Wire Assessment Using a Multilevel PEEC Method

Litz wire (LW) is a common tool used in high-frequency power electronic applications to reduce eddy loss. Uninsulated twisted wire (UTW) with lower manufacturing costs is often ignored by both researchers and designers. LW and UTW have similar geometry structures, however, there has been little research on the performance evaluation of UTW so far. This article proposes a novel calculation method of UTW based on the multilevel partial element equivalent circuit method and the results are verified by the experimental measurement. Then, the performance of LW and UTW is compared and discussed under various conditions. The simulation results show that LW and UTW have almost identical performance and may replace each other for single-level wires. For two-level wires, these two types of wires may be interchangeable when the ratio of bundle radius to skin depth is less than a specific value, otherwise, LW always has a better performance.