High accuracy transient thermal modeling for high-burst motor thermal management system based on phase change materials

Abstract

The motor thermal management system based on solid–liquid phase change materials (SL-PCMs) effectively suppresses transient temperature rises in motors under high-explosion operating conditions. However, the transient thermal behavior of SL-PCMs exhibits significant nonlinearity, which causes difficulties for existing models in terms of convergence or results in reduced accuracy, thus hindering the iterative speed of thermal design in such systems. This study presents two innovations: First, a lumped-parameter thermal network model focusing on the transient melting process of SL-PCM is proposed, which can more efficiently and accurately predict the liquid phase fraction and node temperatures. Second, to address the challenges of traditional solid–liquid interface identification — such as complexity and discreteness — a wavelet transform-based image processing algorithm is introduced. This method not only improves recognition efficiency but also eliminates the uncertainty of traditional edge detection operators in handling ambiguous boundary problems. Experimental results demonstrate the successful continuous identification of the phase interface, with the average error of the proposed model’s predictions improved from 12.1% in existing models to 1.7%. Furthermore, the proposed model is used to evaluate the temperature rise suppression effect of PCM under different heating powers, with results showing that the model offers high predictive accuracy for the system’s thermal limits. The model proposed in this paper holds promising application potential for SL-PCM thermal analysis and design in high-explosion motor thermal management systems.