Novel Lumped-Parameter Thermal Modeling—Part II: Thermal Models for Cylindrical Components and Application to Electrical Machines

The novel lumped-parameter thermal models (LPTMs) have been developed for a general cuboidal component in Part I. In this article (Part II), the proposed thermal modeling method is developed for general cylindrical components in all 1-D directions, 2-D planes, and 3-D solid. By introducing two compensation thermal resistances, both average and midpoint temperatures can be predicted, where the material anisotropy, the distributed loss generation, and the nonuniform heat flow are all considered. Afterward, together with cuboidal LPTMs in Part I, the proposed LPTMs are further applied to establish a complete thermal network for a permanent magnet (PM) synchronous machine (PMSM), whose prediction results exhibit excellent agreement with both the finite element analyses and experimental results. As will also be shown, the proposed LPTMs demonstrate high estimation accuracy, simple modeling complexity, and multitemperature prediction capability in the thermal modeling of complex thermal systems, e.g., electrical machines.