Improved 3D hybrid thermal model for global temperature distribution prediction of interior permanent magnet synchronous motor

Aiming at preventing many undesirable consequences caused by excessive temperature rise, improving the thermal management capability of interior permanent magnet synchronous motor (IPMSM), and promoting the prosperous development of IPMSM in the field of transportation electrification, this article carries out an innovative research around the highly efficient, accurate, and practical temperature prediction technique. An improved three-dimensional hybrid thermal model (3D HTM) is proposed for the fast and exact prediction of the global temperature distribution of IPMSM. First of all, to adequately account for the complex structure of IPMSM in 3D space, the equivalent thermal region is reasonably subdivided by starting from the x-y plane and the cross-section in the z-axis direction, respectively. Next, on the basis of the partial differential equation of the heat flux, the general solution for the associated temperature distribution function is derived by reference to the specific distribution characteristic of the equivalent thermal region. Afterwards, the boundary condition is deduced depending upon the interface feature between neighboring equivalent thermal regions. And further, the smooth construction and solution of 3D HTM is accomplished by incorporating the finite element analysis, lumped parameter thermal network, and iterative strategy. Thereby, the prediction of the global temperature distribution of IPMSM under various complex operating conditions is successfully realized without being constrained by the operating scenarios. Meanwhile, 3D HTM possesses very impressive prediction speed and accuracy. In particular, compared to the currently popular numerical analysis tool (computational fluid dynamics, CFD), nearly 70.00 % or more of the prediction cost, including time cost and storage cost, is saved; moreover, the prediction difference consistently stays below 4.00 %, both for the temperature variation on the comparison path and for the maximum temperatures of critical elements. Ultimately, the validity, sophistication, and practicality of this research are strongly validated by simulation calculation, comparative analysis, and prototype experiment.