A ᐃ T j Reduced Power Module With Inbuilt Phase Change Material for Reliability Enhancement

In a harsh environment, power modules have to be subjected to deep power cycling, which causes large temperature fluctuations and, hence, leads to fatigue stresses. Reducing the junction temperature fluctuation of chips can significantly improve power module reliability. This article proposes a power module design with considerably reduced junction temperature fluctuation by using phase change material (PCM) as a part of thermal management. Cyclical power is applied to the proposed power module, and experiment results show that the reduction of junction temperature fluctuation is effective in a certain range of power periods. Thermodynamic simulations are used to illustrate the mechanism of PCM in reducing junction temperature fluctuation and the factors influencing the optimal range of power periods. With the significant reduction of junction temperature fluctuation, the reliability of the proposed power module is enhanced. The approach is significant to improve the reliability of power modules in power fluctuating conditions.