Improved Thermal Modeling Methodology for Embedded Real-Time Thermal Management System of Automotive Electric Machines

There has been a tendency to embed the theoretical thermal model of electric machines into vehicle thermal management systems to realize real-time temperature prediction and advanced cooling adjustment. The construction process of the high-precision analytical model is the most difficult part for engineering application. However, the electric machines used in electric vehicles usually work in a wide operation space, in which the alternating electromagnetic fields produce different heat production behavior in different operating states. Meanwhile, the major loss components and the main heat transfer paths are highly affected by the temperature variation. The traditional modeling methods usually ignore these effects and oversimplify the model, which will lead to obvious deviations. The main contribution of this article is to propose a theoretical modeling approach with high predicting accuracy in the whole operation space of the electric machines. The experimentally test shows the real-time predicting accuracy has been improved by nearly 60% in a standard test cycle. The computation cost when using the proposed thermal model in the thermal management system is also evaluated to ensure engineering application.