Dynamic Thermal Modeling and Application of Electrical Machine in Hybrid Drives

This paper presents a holistic view of thermal modeling for an electrical machine used in a Hybrid Electrical Vehicle (HEV). This interconnected system model focuses on the thermal assessment of an electrical machine in a HEV application and estimates the time to failure of the machine depending on the construction of the insulation system and the exploitation of the machine. A transient thermal model of the machine is made as a Lumped Parameter Model (LPM) based on dimensions, material properties and Finite Element Analysis (FEA) determining the power loss model and Computational Fluid Dynamics (CFD) cooling model. The LPM thermal model is compared to measurements and later used in a vehicle powertrain model. Based on the verified thermal model, the estimation of the winding temperature in the machine over different driving cycles is used to predict the thermal degradations of the main insulation and the thermal lifetime of the machine.