Identification of Thermal Parameters for PMSMs Based on High-Fidelity Lumped-Parameter Thermal Model

Thermal parameters in permanent magnet synchronous machines (PMSMs) often need to be identified or calibrated due to uncertainties arising from manufacturing and assembly processes. This article develops a general lumped-parameter thermal model (LPTM)-based method to identify the key thermal parameters of PMSMs, including thermal conductivities and thermal capacitances of the main components, interface gaps, and convection coefficients. The developed identification method is applied to various LPTMs to evaluate the applicability and robustness of the identified results. It is shown that the thermal parameters identified by the conventional “I-type” or “T-type” LPTMs are only valid for the same types of LPTMs under the specific load/thermal conditions but not applicable to finite element thermal model (FETM) or other LPTMs. These issues are particularly severe in components with significant temperature gradients, e.g., winding regions. In contrast, when the identification method is performed based on a high-fidelity (HF) LPTM that considers the distributed loss generation and the multidimensional heat flows, the identified parameters closely match actual values and are also applicable to FETM, ensuring that both the LPTM and the FETM remain robust across different load/thermal conditions. A prototype PMSM is used for analysis and validation.