A Thermal Model with the Capability of Characterizing Thermal Coupling Effects for Multi-Chip Power Modules

Abstract

Accurate thermal characterizations of power modules are beneficial for design and operation of power converters with the assistance of thermal models. However, the thermal coupling effects (TCEs) may degrade the performance of thermal models, and this becomes more pronounced in multi-chip power modules. To address this, a thermal model that enables to characterize different types of TCEs is presented in this paper. In the proposed thermal model, the properties of the classical thermal models are first provided. Then, different types of TCEs in multi-chip power modules are thoroughly analyzed. It is revealed from the analysis that the TCEs will affect the junction temperature distributions and heat flows, and distinct thermal behaviors are observed with different TCEs. Afterward, the thermal parameters including the self-thermal parameters and the coupling thermal parameters are extracted, and accordingly, the proposed thermal model is obtained. With the proposed thermal model, accurate thermal characterizations for multi-chip power modules are performed. Finally, taking typical insulated-gate bipolar transistor (IGBT) modules as a case study, the validity of the proposed thermal model under various conditions is confirmed through extensive experimental testing.