A General Arc-Segment Element for Three-Dimensional Thermal Modeling

This paper demonstrates the benefits of a generalized arc-segment lumped parameter thermal equivalent circuit representation that can be used in the 3-D thermal modeling of transformers, wound passive components, and electrical machines. The arc-segment is particularly suited to modeling stator/rotor teeth and end-windings. Commonly used two-resistor lumped parameter thermal networks do not accurately account for internal heat generation, which is essential for accurate temperature prediction. In contrast, the use of a T-network formulation can accurately cater for internal heat generation along with material anisotropy. The element formulation is verified numerically and experimentally using 2-D and 3-D finite element analysis and through the thermal analysis of a power inductor.