Basic Study on the Structural Design for Large-Capacity Litz Wires Using an Equivalent Circuit Model Considering the Path of All Strands

Recently, the equivalent circuit model considering the path of all strands have been considered for the development of large current capacity Litz wires. However, the accuracy and effectiveness of the equivalent circuit model have not been sufficiently verified. Furthermore, the guidelines for the structural design suitable for large-capacity Litz wires have remained unclear. In this study, we measured the AC resistance of commercially available Litz wires. Additionally, we investigated the basic conductor structures for the large-capacity Litz wire. As a result, the experimental and calculated results of the AC resistance of commercially available Litz wires generally agreed. Additionally, the AC resistance increased with the number of strands in the 1st sub-cable. From the above, we clarified that the equivalent circuit model is useful for the structural design of Litz wires. For the structural design of large-capacity Litz wires, it is important to reduce the number of strands in the 1st sub-cable.