Frequency-Domain Thermal Coupling Model for Power Module With Multi-Paralleled Chips

In high-power applications, power modules with multi-paralleled chips have been widely used. The reliability of power electronic devices is intimately tied to thermal characteristics, making the accurate thermal behaviors prediction of power modules with multi-paralleled chips crucial. The existing thermal coupling modeling for multichip power modules typically involves heating individual chips to extract thermal coupling parameters. However, the parallel-connected chips can only be heated simultaneously in the experiment. What is more, the large number of parameters and complicated characterization process in the existing models add challenges to practical applications. In this article, the thermal coupling effect has been analyzed in the frequency domain, and the chips with the same average input loss value are grouped in the characterization process. A frequency-domain thermal coupling model for power modules with multi-paralleled chips is proposed, enabling parameter extraction and thermal behavior prediction through both simulation and experiments. The method reduces the number of parameters and simplifies the characterization process of frequency-domain thermal coupling model without compromising the accuracy of the model compared to the existing methods. The proposed method has been validated through both finite element simulations and experimental measurements.